ish? lol it can be done,but if your no good with spanners then its best left to the pro's.
ive still got mine,its got a cat back custom 'zorst twin exit back box,k+n cone filter with direct air feed +fc chip. est 160bhp
With it being a 5 pot aswell,its like a rocket. I had my mate at the lights in his st170,once in 3rd i was gone..there was another time on a dual carriageway he pulls up next to me,so dropped to second,third and left him..priceless
They are good fun the mk1 hgt's. Theyre not the fastest car around but good fun,oh and the 5 pot warble is nice!