I started off with the same problem, only add about 35 degrees!

 

I went to all the trouble of adding a second oil cooler that only delayed the amount of time till it got hot, but cured nothing.  My next step was going to be to check the vernatherm.  To remove the vernatherm, I had to remove my oil filter adapter.  Fortunately that was the case because I found the wrong gasket under the adapter, blocking most of the passage that sends oil to the cooler.  After I replaced it with the correct gasket, no more temp problems.  If you want to see pics and details, see http://www.n54sg.com/2011/01/second-oil-cooler-upgrade/

 

Although, on warm days, I wouldn't feel bad at all about taxing with temps around 200.  It might hit 210 in the climb, and drop below 200 after level off.  At Reno this year with race power/rpm it was a steady 230ish.  No water or anything.  So at the end of the week I changed the oil, just to be safe.

 

Tom