Your 1.8 should be the abs lump with has 90bhp!! The main difference you'll notice will be much more torque which make the gti feel lots faster when overtaking etc and the gti also has better steering, improved suspension (not just the shocks but the arms,roll bars etc) and much better brakes. All you really need is a better exhaust,air filter and make the suspension stiffer and it will drive much more like the gti is meant to!