I found a Taurus fan for $35 on E-bay. It is a two speed.... I hooked it up (low speed) to a manual on / off switch. I had the temp probe hooked up initially and it went bad and I overheated. To fix it I just hardwired it to the battery to get me home.
Was out at Ocatillo Wells last weekend. 70 degrees outside....runnin hard....but it still didn't get hot enough to turn it on......so no need, so far, for the high speed....low should be fine. I turn it on when my gauge reads 200 degrees. That is what it used to max out at, with the stock engine fan. The temp drops very quickly when I turn it on, and it maintains the temp at arount 180 degrees.
I love it. Follow Jeffy's write-ups and you can't go wrong.