I'm about to get EFI Live and straight pipe my lmm. I"ve got some questions.
1- Would duals make a difference in sound
2- If i'd go with duals and straight pipes how loud would this actually be
3- It will only smoke whenever i really get on it right?

1. They will sound the same as a single 4" system, but give the illusion of a louder kit due to there being a second tail section exiting on the drivers side.

2. Its not what I would consider LOUD. The LMMs sound great with a 4" kit, but if you want it a little more aggressive, get the muffler delete.

3. Yes. Normal driving your truck will not smoke.