Don't even bother with a 4G63 swap that would be a big waste of time and money. The headaches of swaping the 4g63 is not worth it at all. If you ever plan on doing that just buy a TSi it will come out way cheaper. (I'm not hacking the 4g63 I plan on picking up a 1g soon just trying to get the funds). Just adding turbo kit to the 420a will make a big difference. On the way home once from a MCCC meet me and my buddy in a 2g TSI AWD decided to do some pulls on the highway on the way back home. He just got the car so it was pretty much stock with K&N filter and free mods. I had my 420a turboed only at 4psi untuned on stock internals(just installed my turbo setup a week or 2 ago at this point). All 3 runs turned out the same. We downshifted to 3rd @ about 100km/h once I saw him step on it I floored it. Stayed pretty much even for the rest of 3rd but once in 4th I started pulling on him. Went to about 170-180 and I let go and I was about 2 1/2 -3 car lenghts on him. So the 420a is pretty quick when turboed.