It shouldnt void your warranty, things that mess with safety like suspension and engine components void warrantys.Get the straight pipe, my friend has a '89 1500 Chevy with a 305 with 350 heads on it with straight pipe. The thing sounds meaner than hell. Im sure it will sound just as cool on your HEMI.

 

one more factorto consider! Running strait pipes will burn up your valves, which leads to burned rings and so on. It works on the carbureted engines, not the fuel injected. You will want at least a crossover (H-pipe) or an X-pipe. These will actually increase the performance (comparatively) and be safer for the motor.

 

how would it burn the valves?

 

i dont know how whoever has straight pipes can stand them haha...its to damn loud...i have a dak 5.9 and a single pipe straight was to loud sounded like a damned tractor/monster truck/dragster comin down the road...haha yea it was loud and people looked but most likely because they were wondering what just blew out there ear drums

 

I was runnin open headers when my cat was clogged and that was deafening. then my muffler fell off once and i was runnin with just a cat, it ws loud and cool, for awhile, then it gets irrating. Now I am runnin a cat back dual exhaust with a 40 series and it is plently loud enouh when you get on it, and quiet goin down the freeway, but it still turns heads.....lol

 

I have an 03 SLT with the Magnum engine and a Flowmaster 40 seriesto dual exhaust and I like it. Anything louder for everyday usewould not only be obnoxious but it would give me a headache on any long trip. I really gives it that throaty roar at low speed and roars like a lion when you punch it and highway speed. I'd highly recommend it over straight pipes.

 

i have the 4.7 and when i put my gibson super truck on i started it up befroe i put it on yes is had the cat still on it but i wsa loud as hell.........the only drawback it when u get to the high rpms u run a chance of brign ur valves there has to be a certain amount of back pressure r will burn them up