Unfortunately Thomas Holzmann blew the engine at the Verzegnis hillclimb in 2010. There's some Youtube in-car footage of the run, the sequential gearbox was having selection problems and the engine over-revved and one of the big end bolts let go.
The gearbox is a standard 33 unit with a spacer between the backplate and the body housing solenoid shifters - the Alfa gearbox uses a three-rail arrangement which lends itself to this. Its a dog-box as well, of course - no way the synchros would survive the punishment.
Certainly one of the more entertaining boxer racers in recent years!
The other modifications to the engine were cylinder heads with 45° inlet manifolds, you bore out the kink in the tract between the inlet valve and the manifold flange and then insert a straight tube instead.
My hillclimb friend Graham contacted Holzmann Racing to see what they were doing and they sent him these pictures. I don't suppose Mr H will mind too much seeing as he appears to have retired the 33 now...
Its interesting isn't it? I'm not sure where the selection problem was, but you can see "0" coming up on the gear selection display on more than one occasion, so maybe the gearbox had come to the end of its working life anyway.
TBH I wouldn't say no to the remains of the engine - the modified top end may have survived without too much damage, and look at all the dry sump and vernier camshaft goodies!
I've really enjoyed watching the longer sprints that Holzmann has done - where the engine is running at a sustained 9000 rpm on open winding roads. The Verzegnis route seemed particularly bumpy in comparison, which may have contributed to the over-revving. Either way, its a great shame he has given up on the 33.
There are still some formidable Alfas left in German hillclimbing though - check out Gunter Strohmeier's Alfasud - its a 1.4!