A stock a3 with a biturbo and that gearing does over 40. I'd check the compression, it might be way too high with the hihi head. Jetting should be in the 135-155 range with a filter. As far as timing 2.8mm btdc is pretty hot for a tomos, unless you know what the retard curve of it is like. I've never used one of those myself. Usually with the fancier cdi you set them at max advance and it does the rest magically, but sometimes they're static and then retard from there at a pre designated rpm.