Wow,you have replaced alot of parts...including the very expensive lifters!.

Sounds like you have it all under control =)

My only advise is to be VERY careful what pistons you plan to run,from experience JE does not make a forged blank piston that has a similar skirt depth and has sufficent material to cut and make the piston locate the rod on the Mercedes engine.
The other issue is a JE forged piston will have a large piston to wall clearance and will wear much faster.
I wonder if Mahle(mercedes pistons supplier) would do a high pressure cast piston for you?..it might be worth a shot.Forged pistons are really not needed for the power you run,but thats just my opinion!.

This is what my JE piston looked like after 2000km's.,the wear is right through the machine marks.