If you doubt they are his cars, i can tell you they are. Sudo's from way back in LFS and i've seen the build thread of his RX-7, the stagea is sitting in his driveway in the pics.
Trust me, there's nothing more i'd like to do than put an R35 front on it, but for the whole kit, including headlights, wide body sides, and rear, so expensive!
It's for sale at the moment, going to get either a V10 STi or Skyline of some sort next.
Wont exactly be hard to see when you went to see it as there will be a bloody calibra 4x4 floor pan in it which is totally different to the astra one... It's higher up etc... be all running gear at the back.
He isn't going to advertise all that to waste people time.
The engine doesn't look like a V6 to me, I haven't seen that many V6's in an engine bay though, but he puts V6 at every other sentence so I'm guessing it doesn't have one at all.