IMO
1- You'll need sheet aluminum or steel to create your own tin set to redirect airflow
2- CNC a custom fabricated plate to move the accessories package to a horizontal position/plane for fit 'n' function in a teener - this may require a beefier end shaft - then beefier crank/etc - depends on if you have to extend the shaft to accomidate this
3- Good luck with the ECU when you do all of the above
4- It's easier to modify a V-Dub tranny with a 4 speed than the same with a 901, but it would be fun
5- The oil sump area is too small and I believe a separate oil cooler/larger would be needed
6- Everyone will definitely say your car sounds like a Suzuki from the early 80's with any pipe setup
7- Lastly, 90HP aside, the teener body should be all Carbon for weight reduction, sitting on a light tube frame design - that motor was designed to wrap a 180lb groin around if you get my drift
...other than that - Piece of Cake...