be possible if I had to replace my 99.5 oil pan anyway? Is 3.7 to 4.2 a significant enough amount to justify it

I thought only Golf-platform cars had vulnerable oil pans. We've replacedd one TT and 2 GTI pans due to either road or rock contact.

GTI VR6 pan swap in under 2 hours now! Funny, but our local dealers always have one in stock.

...only way to compare them is side-by-side.

Part numbers are probably different from earlier 1.8Ts but that still doesn't tell you anything.

If you take your car in and do not mention that an extra 0.5 qts are required you will always end up underfilled. Most shops never check level after changing, they just add what the manual says.