In this months fast track news bulletin it looks like the SCCA has allowed the 1.8L, but not the 1.4T. Unless I'm understanding this wrong.
Here's the link to the pdf.
http://www.scca.com/assets/12-fastrack-may-solo.pdf
Kind of. Neither engine has been classed in the Stock category. The 1.8 has been classed in the Prepared category (EP specifically). Prepared is for gutted vehicles on slicks with built engines and fully prepped suspensions.
On a side note, I have been running SCCA events in H-Stock (HS) anyway. No one has given me any grief yet.
And yes, I have written yet another letter to the SCCA kindly asking them to remove their craniums from their posteriers.
Edit:
I went back and double checked page 167 of the Solo rulebook. The Sonic
is not on the official excluded list. This is from the may revision of the SCCA solo rulebook which over-rides the Feburary Fastrack.
What does this mean? It means that at the regional level you're good to go, but you still can't run a divisional or national solo.