If a 993 and 986 are on par with each other mileage and maintenance wise, I'd honestly give the 993 the edge as far as being cheaper to own / drive / maintain. The real problem is that they are older than 986's and as a result more incidental / ancillary items will need addressing. I bought mine (1996 C2, not a wide body....damn) from a very nice early 60's lawyer who was not mechanically inclined at all whereas I am. My guess his independent mechanic told him it was on the verge of needing many small items to be dealt with, they would of run a few grand dollar wise for the shop to perform and I did them (hood struts, spoiler bearing, F & R bumper resprays, radio, suspension, replace / touch up some interior bits, etc.) myself for a fraction of what he would of spent.
From browsing this forum since selling my 986 I get continually amazed at the new "failure modes" exposed by Jake and others outside of the IMS bearing (water pump, intermix coolant tank, broken chain paddles, etc.) that would of concerned me. 2 biggest issues for the 993; replacing valve guides as someone else mentioned and SAI issues which can be addressed on a DIY basis. If seriously thinking about making the move I highly recommend Rennlist Forums, they are the 993's version of what this forum is to the Boxsters; the best resource.
