Over 180 is pushing it on these, in my opinion. No data to back that but my B&M cooler keeps things in the 140-160 range under normal driving. This is also with 3/8in barbs in the transmission, all new 3/8 cooler hoses and bypassed radiator cooler.
I monitor mine cosntantly with the ScanGauge. City driving is the worst for it. I often go to 190, even at moderate outside temperatures. Being stuck a while bumper to bumper definitely lifts it above 200. Highway in OD is a little better - about 180 usually. Cruising in D is even better, about 150-170.
I don't use snythetic fluid.