Couple of things have crossed my mind about long term ownerage of a V6 conversion.
1) Oil cap and dip stick are on the front (Firewall bank in an MR2). Dip stick I think could be worked around (I'm thinking Mercs have those very long and flexible dip sticks - Should be easy to adjust) Any others incredibly long dipsticks spring to mind? Oil cap probably liveable with for short term using a funnel, but would it be feasible to machine out a "cap hole" in the second cover?
2) rear bank plugs - just how impossible are they going to be to get to? sure they won't need changing for many a mile (cos I intend putting super long life jobbies in whilst the engine is out) but what if they have to come out?
Have no fear - I'm not going to swap for the easy peasy option of a 2 litre tubby, I'm just trying to plan ahead and fix problems before they happen.