I purchased a DERALE Transmission/Oil Cooler from JC Whitney
a little over a year ago for my 87 190E 2.3 8V. $110.66 plus
shipping. I live in Arizona and wanted a little more help
keeping temps down and I think the cooler has helped (2 Summers and going strong).
I also drilled holes in my thermostat which has also helped!
I have a non-drilled thermostat I use in what we call Winter here.
So far, I rarely see water temps higher than 100C.