This has been quite a learning curve for me, all good and have revised inclination to go for the 10-spd 105. My LBS also advised that since there is life yet in the groupset I could just let them put in the new BB (105 new since 6500 not available), which got done Friday last (20th Mar).

So is it possible that I can increase the gear range, keeping the present 6500 dérailleurs, by changing to compact up front? Then to also add a wider range cassette at rear (while also keeping the present rear wheel)? This would be a great fix for me.