JOHNNYC, Hi. Have a look at my setup. Don't worry about replacing the manifold. Big headache. Run a CP_e down-pipe which includes the cat and plug-in ports for the O2 sensors (see MPS garage site for price and ROGWICK above for photo) good and purposeful but not intrusive or droning. The DP alone gives a significant power & efficiency boost.
Then in your own time you can change the rest of the pipe if you wish, &/or improve the Y junction and change the mufflers and tips when you're ready. I tried (and then removed) the CP_e SS Mufflers and 3" tips and they fit fine inside the oval trims with the possibility of a little sheet metal work with a pair of pliers inside the housings to stop them from hitting if you don't get the muffler mounts exactly right, but IMHO a good custom shop can do that here with SS mufflers that will be efficient but quieter than the CP_e ones.
I haven't bothered with the latter yet as it all sounds good now and works just fine, and I don't want any more noise, and if and when they wear out I'll get a custom shop to make up new SS mufflers with larger tips, say 2.75" dia. for better metal clearance, and a smoother Y all at the same time. The main cat back pipe is a fairly decent diameter anyway (I forget the dia. exactly) and hardly needs to be bigger, but you can go to 3" if you wish. It can drone a bit, however, if you don't get the resonator right.
Last edited by Doug_MPS6; 29-06-2010 at 08:34 PM.
CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18