Connecting rods and pistons
Get ahold of Dave at Modern Muscle Performance Group. He worked with Mahle to create some forged pistons with thicker top ring land; balanced to factory stock specs; (Mahle makes the stock pistons also) so they drop right in. No re-balancing required. He also has some drop in pistons with forged, H-beam rods that are also drop in.
Dave is pretty innovative and has good manufacturer contacts/rapport to do this kind of thing.