Which Tune

Since you have no Tuneboy or PC3 then your dealer is the one to re-tune your ECU and if they know anything they should be able to pick the right tune.

I'd personally ditch any Classic tunes and go with the 20055 "full power" tune, but the 20054 is technically the correct one for your set up as far as the descriptions go.

You might be looking at a different list, old list, or something because your descriptions don't match the codes I have.

My definition of 20051 is the French tune which you should stay very far away from. It will really restrict top end and low gear power.

Based on your descriptions though your "50" matches my "55" and your "51" matches my "54". I'd go with the tune which says "full power no cat".

Review this thread for a run down of throttle restrictions in the various tunes...