you use the existing rear pipe i know that, and the front is a 90 degree bend size being something like 51mm_45mm reducer. Once fitted you should notice is spool up earlier, and you can certainly hear the air blast through, lot more noise, the art is getting them to sit straight, i got my 90 degree pipe off Ebay, watch it don't hit the bonnet though when closed, mine did slightly till i won the fight with the damn thing, dare not take it off now. Any noticeable improvement with be slight, but lets face it the standard unit is no better than a glorified oil cooler, it's got to be better, get it walloped on. something like this : http://cgi.ebay.co.uk/SILICON-HOSE-90-REDU...=item4cec0ee1ec