Check this site out:
Some pretty good info there. I'm in the middle of a complete rebuild of my G26 right now. As far as things to check, check the tightness of the keelbolts, and the condition of the stem piece. The stem piece is cast aluminum, and is prone to breaking. This will bring down the mast, generally a bad thing.
If you want to see all the mods I've done/am planning, PM me.