With a power figure like that Im assuming that he is running an ED30 and not a standard GTI. The next step for stage 2 would be to get a good decent air intake like the Forge Twintake one, a bigger intercooler (again either a Forge one which is pretty decent or the common thing to do is to put an S3 IC in). You will also need a full turbo back exhaust system. There are plenty on the market such as Blueflame and Milltek. I have a FTB Milltek and love it, sounds brilliant and the bigger down pipe and sports cat will allow you to improve the way the car breathes (along with your new air intake). Then take it back and adjust your remap. This will give you some pretty figures and won't be a million miles away from the 300 mark which to be frank is more than enough for a FWD car.
Might be worth considering getting a decent set of tyres (I don't know what your running at the moment?) and bigger brakes.
If you want some inspiration on how to modify an ED30 take a look at this thread -
http://www.golfgtiforum.co.uk/index.php?topic=76660.0 - Its one of the craziest, most amazing cars i've had the privilage to see.
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