Exhaust Guide
Best Exhausts for the
1999 – 2004 Jeep Grand Cherokee WJ: Every Cat-Back Compared
A complete comparison of cat-back exhaust systems for the 1999–2004 Jeep Grand Cherokee WJ — covering the 4.0L inline-six and 4.7L V8. Sound profiles, materials (304 vs 409 stainless vs aluminized), pipe diameter, pricing, and fitment notes from Flowmaster, Borla, Gibson, and MagnaFlow.
At a Glance
Quick Comparison
| Brand / Kit | Sound Profile | Pipe | Material | Fits | Price | |
|---|---|---|---|---|---|---|
| Flowmaster FlowFX | Moderate | 2.5" | 409 SS | 4.0L / 4.7L |
|
SHOP → |
| Gibson Aluminized | Moderate | 2.5" | Aluminized | 02–04 4.0L / 4.7L |
|
SHOP → |
| Gibson Stainless (99–01) | Moderate | 2.5" | 304 SS | 99–01 4.0L / 4.7L |
|
SHOP → |
| Gibson Stainless (02–04) | Moderate | 2.5" | 304 SS | 02–04 4.0L / 4.7L |
|
SHOP → |
| Borla Touring | Touring | 2.25" | 304 SS | 99–04 4.0L / 4.7L |
|
SHOP → |
| MagnaFlow Street Series | Sport | 2.5" | 304 SS | 99–04 4.0L / 4.7L | $904 | SHOP → |
Important
What to Know Before You Buy
Cat-Back Coverage
The 1999–2004 Jeep Grand Cherokee WJ is cat-back only — no axle-back systems are marketed. A cat-back replaces the mid-pipe and mufflers from the catalytic converter back. Full performance gain, improved low-end torque for towing and off-road.
1999–2001 vs 2002–2004 Fitment
Exhaust routing changed between early and late WJ. Gibson offers separate SKUs: 617600 for 99–01, 617805/17805 for 02–04. Flowmaster, Borla, and MagnaFlow cover the full 99–04 range. Verify fitment for your model year.
Materials: 304 vs 409 vs Aluminized
304 stainless is most corrosion-resistant. 409 stainless is budget-friendly and durable. Aluminized is lowest cost; expect shorter life in salt climates. For long-term ownership, 304 SS is the better choice.
Emissions & Warranty
Cat-back systems install behind the factory catalytic converters, so they’re 50-state emissions legal. No tuning required. Flowmaster offers Lifetime Limited Warranty; Borla has Million-Mile Warranty on many systems.
Flowmaster FlowFX Exhaust System: Jeep Grand Cherokee 4.0L / 4.7L 1999 – 2004
Flowmaster FlowFX is the most affordable cat-back in this guide. 2.5-inch mandrel-bent 409 stainless, moderate tone. Fits 1999–2004 Jeep Grand Cherokee WJ with 4.0L I6 or 4.7L V8. Direct bolt-on using factory hanger locations. Lifetime Limited Warranty.
High-mounted tailpipe design protects against off-road damage. The Flow FX straight-through muffler delivers a moderate yet powerful exterior tone. Ideal for daily drivers and light trail use.
Pros
- Lowest-priced cat-back
- 409 SS; Lifetime Limited Warranty
- Fits full 99–04 range; 4.0L and 4.7L
Cons
- 409 SS (not 304)
- Moderate tone; not the loudest
Gibson Single Cat-Back Performance Exhaust Aluminized: Jeep Grand Cherokee WJ 2002 – 2004 (4.0L / 4.7L)
Gibson Aluminized Cat-Back delivers Gibson quality at a mid-range price. Enhances low to mid-range power delivery — ideal for towing and off-road. Fits 2002–2004 Jeep Grand Cherokee Laredo, Limited, Overland, Special Edition with 4.0L I6 or 4.7L V8.
Polished slash-cut tip, single rear exit. Aluminized construction keeps cost down; consider stainless for salt climates. Direct bolt-on; no modifications required.
Pros
- Best value for Gibson quality
- Improved low/mid-range torque
- Fits 02–04 Laredo, Limited, Overland
Cons
- Aluminized; 2002–2004 only
- Less corrosion-resistant than 304 SS
Gibson Single Cat-Back Performance Exhaust Stainless: Jeep Grand Cherokee WJ 1999 – 2001 (4.0L / 4.7L)
Gibson Stainless Steel Cat-Back for 1999–2001 Jeep Grand Cherokee WJ. Full 304 SS, polished slash-cut tip. Enhances low to mid-range power delivery — ideal for climbing grades and towing. Fits Laredo and Limited trims with 4.0L I6 or 4.7L V8.
Balanced, aggressive sound without excessive cabin drone. Direct bolt-on. The top pick for early WJ owners who want 304 stainless quality.
Pros
- 304 stainless; USA-made
- Improved low/mid-range torque
- 1999–2001 Laredo, Limited
Cons
- 1999–2001 only (02–04 has separate SKU)
- Single rear exit
Gibson Stainless Steel Cat-Back Performance Exhaust: Jeep Grand Cherokee WJ 2002 – 2004 (4.0L / 4.7L)
Gibson Stainless Steel Cat-Back for 2002–2004 Jeep Grand Cherokee WJ. Full 304 SS, polished slash-cut tip. Fits Laredo, Limited, Overland, Special Edition with 4.0L I6 or 4.7L V8. Refined exhaust note, improved throttle response.
Ideal for daily driving, towing, and off-road. Balanced sound without excessive cabin drone. Direct bolt-on.
Pros
- 304 stainless; USA-made
- Fits 02–04 Laredo, Limited, Overland, SE
- Balanced sound; no excessive drone
Cons
- 2002–2004 only
- Single rear exit
Borla Cat-Back Exhaust: Jeep Grand Cherokee (99–04) 4.0–4.7L w/ Chrome Tip
Borla Touring Cat-Back delivers a mellow Touring sound with no interior drone. 2.25-inch T-304 stainless, 4-inch bright chrome tip. Fits 1999–2004 Jeep Grand Cherokee Limited, Laredo, and 2002 Cherokee Sport with 4.0L or 4.7L. Million-Mile Warranty.
Borla’s straight-through and multi-core technology improves exhaust velocity, throttle response, and fuel efficiency. Ideal for daily drivers who want a refined exhaust note without highway drone.
Pros
- Touring sound; no cabin drone
- 304 SS; Million-Mile Warranty
- Fits full 99–04 range; 4.0L and 4.7L
Cons
- Mellow tone; not aggressive
- Premium price
MagnaFlow Street Series Cat-Back Exhaust System: Jeep Grand Cherokee WJ 1999 – 2004 (4.0L / 4.7L)
MagnaFlow Street Series Cat-Back delivers a distinctive, resonant tone that enhances your Jeep’s presence. Full 304 stainless, 2.5-inch mandrel-bent. Fits 1999–2004 Jeep Grand Cherokee Laredo, Limited, Overland, Special Edition with 4.0L I6 or 4.7L V8.
Balances aggressive exhaust notes with refined interior sound levels. Polished 4-inch double-wall tips. Direct bolt-on. One of the best-sounding options for the WJ.
Pros
- 304 stainless; sporty tone
- Fits full 99–04 range; all trims
- Polished 4-inch tips; direct bolt-on
Cons
- Premium price
- Can drone at cruise (less than aggressive systems)
Fitment Reference
Which Kits Fit Your Trim?
| Trim / Year | Flowmaster | Gibson Alum | Gibson SS 99–01 | Gibson SS 02–04 | Borla | MagnaFlow |
|---|---|---|---|---|---|---|
| Grand Cherokee WJ 1999–2001 (4.0L / 4.7L) | ✓ | ✗ | ✓ | ✗ | ✓ | ✓ |
| Grand Cherokee WJ 2002–2004 (4.0L / 4.7L) | ✓ | ✓ | ✗ | ✓ | ✓ | ✓ |
✓ = Confirmed • ✗ = Excluded
Common Questions
Frequently Asked Questions
Why are there no axle-back options for the WJ?
The 1999–2004 Jeep Grand Cherokee WJ is a cat-back-only platform. Manufacturers offer full cat-back systems. A cat-back provides the complete performance and sound upgrade, and improves low-end torque for towing and off-road.
Will an aftermarket exhaust void my warranty?
Cat-back systems install behind the factory catalytic converters and do not affect emissions equipment. They generally do not void the vehicle warranty. Check with your dealer if concerned.
Do exhaust systems improve towing performance?
Yes. Cat-back systems reduce backpressure and improve exhaust flow, which can improve low-end torque and throttle response. Gibson and MagnaFlow market their WJ systems for towing and off-road. Expect modest gains (5–10 HP / lb-ft).
1999–2001 vs 2002–2004: what’s the difference?
Exhaust routing changed between early and late WJ. Gibson offers separate SKUs: 617600 for 99–01, 617805/17805 for 02–04. Flowmaster, Borla, and MagnaFlow cover the full 99–04 range with a single system.
What causes exhaust drone and how do I avoid it?
Drone is resonance at certain RPMs that amplifies inside the cabin. Borla Touring is tuned for no drone. Flowmaster and Gibson offer moderate tones. MagnaFlow Street Series can have some drone at cruise. Research sound clips before buying.
304 vs 409 stainless steel: which is better?
304 stainless is more corrosion-resistant and premium. 409 stainless is budget-friendly and still durable. For salt climates or long-term ownership, 304 SS is the better choice. Aluminized is lowest cost but has the shortest life.
Ready to Upgrade Your Jeep Grand Cherokee WJ Exhaust?
Compare cat-backs above, pick the right fit for your year and engine, and order with confidence. Need help? Contact us.
