I have a late model ST that has no VIN stamped it as odd as it sounds. The VIN sticker was gone too when I got it. Depending on what you want to do, I went through the titling process using the motor motor serial number. The motor serial is clearly identifiable.
I've never seen a Kickstart A3 they seem interesting.
Your story sounds so weird and sketchy. You're lucky you didn't buy a Targa LX with this motor it!
