when I spoke to awesome about this they seemed quite comfortable putting 400bhp through the BAM engine and said timing was the main reason they can achieve such a high power without replacing the internals
 
The S3 derived TFSI engine uses stronger internals over the normal 200PS models so i've heard.

My only main concern with BT on TFSI is how the DSG box will cope (if you've got one). Uprated clutch cassettes are very thin on the ground with prices upward of £1500.