Im about to put some high flows on and was wondering i have a si/do flowmaster . Should i switch it and do true duels with an x-pipe or is there not that much difference to waste money on it?

 

I would try it with your SI/DO first to see if you like the way it sounds. The high flows will make a lot louder, if you can always add to the system. I'm happy with my SI/DO, I was going to do the X pipe but I don't think it will make that much of a difference with performance.

 

Unless your putting out some serious HP stick with the SIDO. Duals would be a waste.

 

thanks if the cats truely will increase the sound then that should be enough mods. what is up with all this i hear about the 4 cats vs 2 high flows being illegal and stuff am i going to be able to do it?

 

high flows aren't illegal. they burn cleaner than the stock 4 cats. if the muffler man doesn't want to put them on for "legal" reasons, cut the stock cats off, and bring your high flows to him, and ask him to "fix" it for you.

 

Well ofcoarse keep your exhaust and just add the Hi-Flows in.