Solstice with the LNF has to run 2820# and a 34mm restrictor, and it has to remove -2mm for RWD. That's a 32mm hole; there's no way they're putting out even close to those numbers for STU.

If you can get the S14/S15 chassis down to 2675#, then you're running a 31mm hole. 1mm down but also 135# down.

The old SR20DET would be hard-pressed to compete with the technology of the Ecotec LNF, but in general this isn't a terrible pairing. And, if someone builds one and demonstrates it, it has the opportunity to drop that -2mm.

Build it.