stock internals are perfectly fine
Its all in the tuning.

Theres a guy you migt want to talk to that has successfully installed an aem fic-8 on a clk430 turbo he built.
I've been meaning to contact him because im curious as to the following. which tps wire you tap,
and how the aem controls the coilpacks for dual plug per cylinder, since iirc the ignition sequence is staggered at high rpms which means each coil is getting two seperate signals (or maybe its built into the coil, im not sure)

I'm going to rebuild the pump as well and i will give you a hell of a deal on it should you need it just trying to help out) i got it as a spare but doubt i'll need it.

the m112 based motors are surprisingly strong. although the pistons are cast and iron coated (not forged, like we thought)

I'm trying to see what it would take to get a set or arp headstuds made for these motors (since the 112 and 113 share the same bolt design) because from what i can see now, the weaknesses of these motors are (for fi use) the stock head bolts and the headgaskets, since if we could have a thicker headgasket made we could drop compression.

i'm also stumped as to the fuel pump to run. im looking for the pierburg "800" but everything i've found says its the standard pump mercedes uses in all its cars?!?
and im looking for an e55 amg maf (but i think the v8 motors all use the same maf)

AND (sorry) i'd be curious to see if you can get a higher stall torque converter.

sorry for the rambling, but the more info we can get upfront the better off we are.