180*. I initially installed a 160* when I installed my KB (it's what KB recommended) and the computer would stay in open loop (this is not a good thing). The 180* has been perfect.
i dont go so much by the stat rating as much as the temps that the motor actually runs at. some folks run a 160 to keep temps around 220 - when cooling systems could use upgrading/renewing.
others run 2* over the stat rating.
a 160 should get the car into partial closed loop - at idle or steady throttle, it can be in CL. but in dynamic situations (accelerating, etc), it can revert to open loop.
in general, running 185-195 or 200 is good with me.