You might find the gearing of your standard box will be too long for your new engine. You'll probably have peak power at around 8200rpm and find yourself revving to 9k. You're going to be geared for about 180mph. I'm not sure if there are any shorter CWP's available anywhere for the GTI box though. There are dog boxes and sequentials available from Germany in the 085 bellhousing pattern, which is Polo GTI fitment. You also occasionally see Gemini sequentials for sale on racecarsdirect. Again 085 fitment.