Well I tried FW1.5 and 1.4 but it (luckily) had no effect on the error reading. It was till quite slow. This means that Plextor firmware is not to blame in my case. To make sure I tried reading errors from an original disc with SafeDisc protection. It worked very fast! I think the back-up SafeDisc protected games are getting old (I tried 3 games which all had the same problemf but this is just a coincidence).

This doesn't answer your question I know but isn't your disc scratched because it finds error. I'm pretty convinced the SubChannel Data works fine in your case but I can't be sure. Can't you try a different SecuROM protected game or a PSX (LibCrypt) protected game? Maybe your SimCity 3000 isn't good...

Greets!