If it is a package they would make sure that would have a lower time frame to do it and ship it back, so that equal less time to have the car stopped. also the price would be in only one invoice from them to my company with a good discount to all, and I would share a copy of the invoice with everyone that got on the deal so everyone knows how much you are really paying for.
In my setup I will have AA headers, Custom SS modified middle section pipe and straight pipes to the muffler also modified race eissmann. what would increase even more the speed of the exhaust.
This all should give quite a boost in power.