Interesting car, but you would have to love Targas.
I am not sure how they get 3433cc, as the 3.4 conversions are actually more like 3350cc and the 3.5 conversions are true 3500cc. Ruf typically did 3.4s with special Mahle pistons and barrels that were much like the Max Moritz conversions. This is a Motronic 3.2 (presumable rebuilt to 3.350 litres), which has not had its intake cut open and bored out so it might make 280hp, but not without cams and a nice exhaust. Not enough details to tell. A 3.4 with 964 cams, honed intake and B&B headers will make 275hp, so I think 280hp is a tad optimistic. It will never run 191mph but the description just says its geared for 191mph. Accordingly, 6th will be a massively overdriven cruising gear. It will do about 165mph flat out, probably in 5th not 6th.
If it has a 6 speed G50 trans as described, then it must be a short bellhousing trans to fit in the 1989 torsion tube. It will even then have the engine mounts moved back a little to accomodate, according to all I have read. Most people doing 6 speed conversions cut out the torsion tube and run coilovers - even in G50 cars like this one.
Its a great car for a cruiser I guess. Turbo suspension means the same torsion bars at the front and 1mm bigger at the rear, though it will have Ruf bespoke damper settings for probably Bilstein legs. It will be torquey, comfortable and long-legged. Nice big brakes, but very expensive rotors for this set-up. They are 1978-79 930 rotors, floating or non-floating, on custom zero offset mounting bells for this narrow body application. Price depends on whether the Ruf name can lift it above the "modified" discount mentality. Its not a yellowbird and the incorrect front bumper hurts initial perception. If it was a coupe in top condition, I think it might fetch over £20,000 because its punches into the market for the CS cars and even the bottom of the 964RS market. As a Targa its more of an orphan and doesn't quite fit the buyer profile of the other specialist cars IMHO, but then it only takes 2 keen buyers to start bidding.
RB