I have not started my build yet but the Edge EP914Ti is at the top of my list. It's a turbo with FI and costs the same as a stock 914 and even weighs a bit less.
The Edge products void the Rotax warranty but Edge offers their own warranty that's almost as long. I chose it for the following reasons:

1) Has FI so I don't have to worry about carb icing
2) Lower fuel burn
3) Turbo, so full power up to 15,000 ft
4) Cost is $6k less than 915is
5) TBO for 914 is 2000 hrs whereas 915 is 1200 hrs since it's a new product
6) Weighs 40 lbs less than 915is

Choosing between the SS7 and STi is really a matter of mission. The takeoff/landing roll of the STi is about 50% of the SS7 but the SS7 is
still low at 290ft. The cruise speed of the STi is 105 mph and it's 123 mph for the SS7. For me, I'd like to have reasonable STOL performance but enough
speed to get somewhere in a reasonable amount of time. For those reasons the SS7 is my choice. You'll have to decide which is more
important: Speed or STOL.

Victor