Had my 95 WRX Jap Import for a couple of weeks and once i sort the slight burning smell/squeek out (see previous post) what should i do next, chips,cams etc.Can anyone recommend anyone in yorkshire to do the work?

The car has a HKS exhaust and HKS air filter already fitted and seems pretty rapid to me, though i was driving a VTS before, but i would like a little bit more.Should i get it re-mapped for our fuel or is it better to keep using Shell V-Power?