im not that up on it myself man but one of my mates does it through his business,
but as far as i know u get a nice bhp increase and improved fuel efficency!

theres his thread about it on MNC

http://www.midnightclub.ie/forum/showthread.php?t=45093

his name is Mike
give him a buzz and im sure he will be able to price up whatever you want
hes based out of limerick and sligo,
he will look after ya

heres his number
0861736455