When buying an exaust ffrom my local vag garage, they sell the milltech system in two parts, the larger bore down pip[e and sports cat, for £390 fitted, is this the part that basically gives you more performance, or would i need the whole lot, im asking as im not really bothered about noise or style of the twin jets at the back, if i need it for performance ill get it. I think ill need the dwnpip[e etc to get a chance of getting around 220 225 bhp off of my remap im saving for.