Removing Leading Track #s, ...but not in certain instances. Options

[InfaredFog]

I read the post about common functions that suggested using this to remove track numbers:
Regular expression: ^\s*[0-9]+\s*-\s*

While that half works, there's a few changes I'm not sure of how to implement.

1. It removes 311 from filenames, which is a band name, not a track number.
2. If I want it to remove track numbers that don't have dashes (e.g. 01 panasonic youth.mp3), would I remove the -\s* in the above strong?
2b. Also, if I do this, how would I make it so it didn't remove these numbers: 69 (69 Eyes) and 88 (88 Fingers Louie)?

Thanks for help in advance.

P.S. I've been unable to convert .m4a's to .mp3's, anyone have any experience with this?