I haven't sprung for the TCPI4 yet, but I can give you some indication from doing a crude advance on the pickup coils. I used the same technique as setting them closer, filing not only the lateral but the vertical edges of the mounting holes. Moving the timing just 3 degrees will get you into trouble off-idle and up to about 1500 rpms. By that I mean it immediately requires premium to prevent serious knock. There is no increase in torque, but, the engine comes alive much sooner, around 5500 instead of 6500, and it pulls significantly better above 7500. Looking at the curves for other bikes with similar strokes and cam timings, my guess would be there's a little more to be gained if you advance 2-3 more degrees beyond that between 7500-9000 (yes, Veronica, the VN will spin there easily). But I would be very cautious of bringing in any more than 4 degrees advance below 5000. And yes, rejet.