GTM posted a picture comparing the stock connecting rods between the HR, VHR, and DE motors a long time ago. I saved the picture because I knew it would be useful at some point.
From left to right; HR, VHR, DE:
I have posed similar questions to boosting powerhouses like GTM, AAM, and Injected Performance. After talking to them, I have concluded that about 430-450 hp on the street is perfectly fine on the stock block. The beauty of the TT though is adjustability on the fly with a boost controller. If I were to take it to a road track every now and then, I'd definitely kick that boost down a few just so I'm not pushing it. I hope this helps.