I'm in the middle of an engine swap, going to a 5.9l and I've got shorty headers alread 2.5in . and I was wondering if a 3 inch exhaust duals with h pipe would be enough backpressure so that I won't loose power. I don't want to go all the way back, just thinking of dropping them before the rear end . would this be enough backpressure ? and what type of muffler should I try?