I'm about to do some re-rigging on my Formula 242. I'm adding K-Planes and am wondering if there is any benifit to having any moveable weight such as trim pumps and batterys mounted forward or back in the engine compartment.

Depends on your boats balance. If it bow heavy you need to move what you can as far back as you can and vice versa if stern heavy.

My boat is bow heavy, so moving things to the stern should help, which is what I was thinking..

Generally speaking, coventional bottom boats will do better with the weight more to the rear, or transom.