Catdog, I installed two aileron servos, it was quite easy. If you haven't done them before, my top tip is to feed the servo extension wire through before you cover, as it is a nightmare after.

IMHO there is no need to beef up the undercarriage mounts. I built mine stock, and no problems in the three years it has been flying. The wire legs themselves have both snapped, now replade by 8guage wire instead of 6, as it is easier to bend and more springy.

As for saving weight, depends on how much work you want to do. From memory the ribs are solid, so you could put lightening holes in them. Check the quality and weight of the wood throughout.

Also watch out for the balance, mine came out quite nose heavy, though the FX is heavy with the standard silencer. I installed flaps, looks cool but doesn't make that much difference.