You can contact Josh Chase at teh Mercedes Swap Shop, I'm sure he'd tell you not to bother and just get an SRT or let him put a V8 in for you - but if you insist, I know he can do it.
Just a matter of how much money you are willing to spend. I'd imagine the V8 swap would be no more expensive and less likely to fail - the N/A internals are simply not designed for it.

DJ in Arizona did charge his little Red Coupe six speed. I almost bought it, but again, it's a one-off and NO ONE can help you if you have issues with it, other than a Josh Chase. Again, I think the V8 swap would be my go-to mod.

Here is how to contact Josh:
https://themercedesswapshop.com/