If you looking at £159, then I would recommend you go for any of these :
Hayward & Scott downpipe cat removal @ £182
http://www.haywardandscott.com/Details. ... ategory=13
ScoobyWorld AfterBurner @ £171 (made by H&S)
http://www.scoobyworld.co.uk/catalog/pr ... cts_id=447
2nd cat removel an additional £100 :
http://www.scoobyworld.co.uk/catalog/pr ... cts_id=179
Revolution @ £219 but also does away with 2nd cat (double check with them though, as the picture looks like the pipe is long enough to remove 2nd cat)
http://www.revolution247.com/exhausts-m ... 461-0.html