ain't nothing wrong with performance tuning with any size engine. its fun.
anyway, how does one measure the exhaust diameter? inner or outer? I'd like to know what i have!
The suzuki samurai FSM does mention backpressure but only as a component in the EGR system, it "needs" it to function correctly.
See, back pressure has it's purpose!
Here is my experience on exhausts:
Way back in 2001, I replaced the stock exhaust system with a
EDIT! 2.25", NOT 1.25" exhaust, a Thorley header, a cat converter and some sort of high-flow muffler the muffler shop guy chose. Except for the Thorley, the entire system was installed by the muffler shop for around $200.00.
Right then and there, I KNEW I had done something right! That old 1.3 ran a LOT better!
Oh, and the owner was a Russian immigrant who really knows his stuff and is a DANGED NICE GUY!! I recommend him to everyone who asks about muffler shops in Kansas City.