For your first point, I haven't gotten around to updating the guest times since like mid-March. I'll probably work on that this weekend.
Retrospectively, the old Blaze Canyon colors were rather samey/drab, with brown walls coupled with brown dirt combined with brown ceilings. Given how colorful Sonic games generally are, it always felt a bit...mismatched with every other level. But I can understand that the "brightness" is off-putting. I'll try and come up with a different color scheme.
As for the speed shoes music, I feel that I'd have to find appropriate / non ear grating invincibility music as well, which is kind of why I've left it as the default all this time. It would feel kind of silly to change one and not the other. Any suggestions(NOT sonic 3/sonic cd)?