i got a custom exhaust from rebal power pipes in barton (near hull) i got a turbo downpipe, decat and then straight through pipe to the back box. it cost £283 in all, and im really happy with it. iv deffinitely noticed that the turbo spools up quicker (about 250rpm sooner) the whistle from the turbo is alot louder and makes a really nice sound at about 3000rpm and higher, but a nice tone when driving around town etc.
at some point im going to un-bolt the back-box to see if the sound is any louder and better, and if it is, the guy who made the exhaust at rebal said he would take it off and replace it with just a pipe.
oh yes and also, after i got the exhaust fitted i haven't noticed hardly any smoke, there was abit of a wierd smell when i fisrt got it done but now its gone. maybe the smell was
stickers or seals on the pipe work that was melting, i don't know