Kasman,
I'd remove the oriface plate and install a 180 degree t-stat and call it a day. There's no reason what so ever not to run a t-stat in a street driven car. Beyond that your temperatures don't sound unreasonable. People seem to worry when a motor exceeds 180 or 190 F, but you don't need to worry unless it actually boils. If you run
antifreeze and you have a good 12psi radiator cap, your engine won't boil until you hit 220 or 230 F or so.
Chris