Sorry to bring up an old(ish) thread but I really like the info and wanted to say thanks.

I don't have a 400E but I'm looking to buy one next year.

A few questions:
Have you considered going to standalone EMS? E.g. Megasquirt?
If I haven't bought one yet, which is the best year to buy, and why?
Do you like open deck or closed deck more? Coming from 944 turbos, I hate open deck (blows head gaskets all the time), although on the non-turbos it's not a problem.
Do you have plans to change your differential?

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo