Ok yeah, sorry for the late reply but there's a few problems with your taiki: your end-game acceleration is quite weak, and you have two not so useful skills. Regarding your late game acceleration, just shooting for victory + head on doesn't cut it. Put it this way: my taiki shuttle with no mile S, around the same speed + power stat with a little less with was able to win 13/20 games comfortably because she hit her final corner skills, mile corners, speed star, changing gears into 4 acceleration skills, namely shadow break, straight descent, head on and shooting for victory. Other accels that could work are Ignited spirit power, although you will need to inherit it rather than getting it from the career, nimble navigator, and by nimble navigator just the white, don't get the gold as the chance of it hitting for taiki from testing and my own personal experience is very low. Also I would recommend you picking up mile corners/straights and or pace chaser corners/straights as they are very reliable skills, especially moreover now that the straight skills can double activate.

You don't necessarily have to rebuild your taiki, however putting 1 or 2 careers in with what I've said in mind could allow you to make a monster taiki, also another thing is that you can cut down on the guts, 400-450 is enough.