Nice work. I've modded blubblers timer to autosplit too (http://pastebin.com/zxqkXu1g) but I'm not much of a coder.

One thing on the splits: For whatever reason, looking at when 0x075F and 0x075C/0x0760 change doesn't work when using a warp zone. When you hit a pipe in a warp zone, 0x075F and 0x075C/0x0760 change immediately when you hit the pipe. However, the frame rule is factored in sometime after that when the lives screen is displayed. The only way I could get it to work was to see when 0x075F or 0x075C changed then when 0x0772 = 2. This ends up splitting right after the lives screen.

The mods might need to weigh in on the legality of using the 4-2 xpos display during actual runs. It may be considered too much of a "tool assistance" although I think everyone is just doing a 3-bump 4-2 at this point anyway.