There are not a lot of performance improvements to be made on these engines. Mercedes engineered them pretty well. On the M130 you can put in a European cam and gain some improvement, but those cams will set you back more than a few $$. The Mercedes bottom ends are pretty solid, do a compression test before you decide to abandon the block. A Valve job might be all that is needed. If you do decide to swap to a M110 do a thorough job of planning the project and price all the parts before you commit. Engine swaps are rarely straight forward. Your costs can balloon pretty rapidly if you are not careful.