I have oil coolers on both my cars.
Looking at both engines and their milages since rebuilt I think in my case it was a worthwhile investment.
But than I use my cars mainly for long distance tours and road rallyes.
The Sprint, despite being fully trashed for more then 60.000 miles still has very good oil pressure.
If you are going to use the car for gentle tours only I wouldn't bother.
Just buy decent (20W50) oil and change on a regular basis.
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<font color="blue"><i>1980 TR7 DHC (my first car, currently being restored)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="2"><font color="red">My Weblog</font id="red"></font id="size2"></b></u>[/url]</b></i></center>