what would the hp be?

[EvilAngel]

I dont think efi would increase (at leastnot substantially) hp from a well tuned carb system. But it does help reliability as it has less moving parts that can fail, and it really improves mileage. Also it opnes a lot of possibilities for fine tuning.
Also if you have EFI & turbo, i don't see why would you suffer from drivability if properly set up. I do think you'll suffer if using carbs + turbo, but this may be negligible if the setup is perfect. I have read in both the samba, STF and VZi of people with small displacement turbo engines and love it... Im just looking for more torque.