I can almost guarantee your not going to hit 500+ with the IP kit and a exhaust system with the your requirements.

 

i have seen low 400's on stockish exhausts but not too much higher than that.

if you want to be quiet and get the most performance out of your car i'd recommend keeping the stock exhaust and getting a 3" cutout. it will make the most power, keep you as quiet as stock, and also be the least expensive!

 

Whats a 3" cutout? Do you mean replacing some parts of the stock system? Sorry I am not very into exhausts yet, but I am in the same position as the OP. Not his power goals tho. I am happy with 350whp, but plan to make the setup efficient.

I have also had some ideas about making my own system from the cat and back.

 

a cutout system incorporates basically a big "T" into the system.

picture your stock catback exhaust mating up to a 3" downpipe. obviously there will be a step down in piping size. now in between the 2" catback and the 3" downpipe put a T pipe in between - you'll have an extra 3" pipe that seems to fork out at an angle. place a throttle body type plate in that pipe and wire it up to an electronic control that can open it whenever you want. the result is a quiet stock exhaust when the plate is closed and an open downpipe beast when it's open! you get the best of both worlds in a sense.

look up electronic cutout on google and you will find pictures that will definitely help my explanation out.

 

hey siadam thanks for the link however it didn't show anything

 

if your expecting 500hp your going to have to swap out the exhaust. Nothing will be as quiet as stock, but you'd have to deal with it if your wanting that much power.

 

Hmm.. that seems to be a neat solution, yet a bit complicated. I don't have the demands of super quiet stock exhaust, I had a skunk 2 with removed inserts on my last car and with the turbo the car was acceptable to drive.

I am abit worried about the electronic cutout. Pone that you tune the car with the free flowing exhaust, then I feel it might be possible to run into problems with the restrictive exhaust. Better not risk that.

I think I am much better off with a compromise that works all the time.
Besides, I like when the car sounds aggressive. It is not a beater, just a summer car after all.

What do you guys think would be a good route if making your own exhaust? How much sound dampening is required to minimize droning?

Maybe the cutout is the way to go for the OP with the high power goals and silence requirements.

 

3" piping with a 3" resonator and 2 smaller 3" mufflers. Even then your going to have a hard time hitting 500+

 

quiet and 500whp don't go together on the same car.

 

I would say:
Invidia Q300-low price choice 70mm
Asura-best dual option
UR-alt dual option
Asura-new single seem to do a lot of testing for sound and performance
3" Inline Pro Single-most HP for your set up
Make your own