Hello Martincho, Funny to see one of these bikes to pop up .. Is this bike in Chile ?
The rear derailleur is not original, factory default it was Sachs Neos. Personally I wouldn't mind if a better derailleur is installed, since this Neos line is not that high-end.... When you're a purist who wants the bike restored in it's factory state, I still have the original parts somewhere in my basement.. I can look them up for you. The rest of the bike looks stock to me.
If you buy it, take a good look around that missing paint... These bikes were painted by Porsche with the same paint as used on cars (powder coated). Quite durable. The absence of paint could be caused by a hit.. Take a thorough look to spot any cracks / dents...
p.s. The saddle seems to be changed, originally it has an Expedia saddle... But bikes from these days all should have a Sella Italia Titanium Flite
1996 Votec Porsche Bike S
1998 Cannondale Killer V 800