Jesse Kloth from SDG Motorsports was looking at doing more adapter plates if you wanted to go down the Torqueflite route. I can't remember what Jesse's user name is on here, I think I have his email somewhere.

The kit Leon does is very good and headache free, for a GM based trans it would be the only way to go.

From memory, the Nascar headers don't fit particularly well in a door car, I think any of the cars I have seen have had custom headers.

I am still building my engine, so I can't comment how fitting it to the car, plus my steering is on the opposite side anyway.

Best of luck