My 87 was a basic SQ swap to start with, except for stating with a 14G that came with the donor car. It began as an 87 SQ that, so TB EFI, and was quickly upgraded to 88-89. It now has 2" hardpipes and a gutted pre-cat with 2.5" exhaust the rest of the way back. The BOV pops nicely these days when I shift it.

If you are patient and get your donor parts for the right prices, you will spend no more that you will for the Weber, and have a setup that is time-tested at this point. I got mine for $750 with a trunk full of parts. By the time I sold the extras and parted out what else I didn't need, I got all my money back, making my swap free. (Aside from decisions to rebuild the motor and put a new head on it. But that was relatively cheap for having a new motor in the end.)

I have no real experience with the Weber, or Mikuni for that matter. I just know how easy the SW swap was for me as a relative noob.

My sense is don't do the Weber if you are going to do the turbo, and vice-versa.