Help with mods

[David]

I've had my HGT155 for just over two years now, had since new. At the moment the only mod I've done is change the standard alloys for 16in ones. Thinking about fitting a pipercross induction kit. Don't know whether to get the standard kit or the viper, is it worth the extra money? I want the fitting to be completely reversable, I don't want to have to cut things etc. in the engine bay to make it fit.
If I fit an induction kit do I need to change the exhaust to get the maximum beneift?
I'm also looking at getting a rolling road performance test done before I do any mods, any one recommend a place with the East Midlands/Nottinghamshire area.