Tony is know for his fantastic tunes and his free reburns unlike the others that will charge you.
Single shots will only be a little louder than splits at idle but will give you better fuel mileage!
I'd go with stage 1's or 2's
Check your turbo and see if it has a WW installed ...to help get rid of surge.
With bigger inj. you will need to upgrade your clutch as a stock one will not hold the HP.
Cary