Changing the centre pipe only doesn't do too much but it's a start. My spyder came with standard centre and rear but Larini sports cats. Sounded ok but not much louder than standard. When I added straight through rears (but keeping the standard centre) the sound levels increased markedly. I ran that system for about 18 months and then put on a straght through centre exactly the same as the one in the picture. That is my 'Le Mans' spec and they guys who were there will tell you, it's VERY loud. I have now changed the rears over to the SM modified GS boxes and that seems to be a better compromise. It's difficult for me to suggest which is the best system because the spyder doesn't have the same internal acoustics as a coupe so we dont get afflicted by resonance in the same way. The modified GS boxes don't seem to have the 'boom' periods between 2000-4000rpm but has the 'crackle' associated with a race type exhaust so that may well be the way forward. However, It has become clear that changing one part in isolation doesn't do too much but changing two certainly does. IMO, changing the cats (removing 2 and replacing the other 2 with 200 cells cats) is probably the best starting point. Then you can decide just how much noise you want and go from there. There is a thread (SM exhausts IIRC) which has video of various exhaust combinations. Pm me if you want any more info or suggestions.
