I priced it doing my own work. I figure $4,200 to bump up to 3.7 liter and that's with stock oem Mercedes parts and aftermarket accessories like cams and ecu tune.

Now I haven't been able to get dimensions on the block yet, but if its possible to bore it for 100mm sleeves and get new piston's milled it will cost me $300/piston and about $200 a sleeve.

Not sure what your intentions are? I hope your not paying someone else to do the job.