Does anyone know when re-flashing the computor, if you bump up the timing to much if this can harm the engine over a period of time. I read that Brenspeed he is running 12.8 E.T. at 107 , one thing he has done is to bump the timing up quite high.

 

It won't hurt your engine one bit unless your car is running too lean. To run a lot of timing, you need good gas and a very precise tune. Getting too agresive on the timing can cause disaster, but done properly can increase hp substancially.