If your PCM is tuned for it, the 160 t-stat works fine. The problem is most people here have the stock computer, or their chips aren't programmed for the 160 t-stat. There is no reason to run the engine hotter than 160 degrees other than to keep the computer happy and for emissions purposes IMO. Our GTP has a drilled 160* t-stat and it runs very well, gets very good gas mileage, and since the computer knows its there, its just like if it had a 195, only it doesn't get as warm. It helps kill KR and keep underhood temps cooler, which in turn makes things last longer and kills KR more. The GTP will still warm up pretty quickly so you have warm heat too. And the GTP is primarily a street car, racing it is just a hobby on the side, so its not like the t-stat makes it un-streetable. My dads goal with the GTP is to keep it as streetable as he can and still make it fast, and it really is just as streetable as it was stock.
Our Turbo GP coupe also has a chip and a drilled 160 t-stat (that is tuned into the chip) and it runs very well, stays very cold, and still pours out the heat quickly. It also doesn't appear to kill gas mileage any.
I wouldn't recommend it if your computer is programmed for it, but if you got a chip/reprogrammed computer it would be a great mod IMO. Otherwise put in a drilled 180, and that will still help a bit. (just a 180 t-stat has show a 2whp gain on a stock GTP)
1990 Maroon Grand Prix STE McLaren 3.1 Intercooled Turbo, 14.695 @ 94.49 on 12psi before cam/heads/etc.
1990 Bright Red Grand Prix McLaren 3.1 Intercooled Turbo, 14.819 @ 92.72, 189whp
1999 Grand Prix GT 9.75:1|K&N|160 tstat|No Ubend/Cat/Res|UD Pulleys|Ported M90/TB/Heads|XPZ|2.55"|Pacesetters|Stage 2 I/C. 12.442 @ 112.78
2000 Blue Bonneville SSEi Supercharged Gutted Airbox|K&N|3.4"|1.9'*|WP Pulley|Custom DHP|180*stat|41932'*|No Cat. 14.681 @ 94.80
2002 Dark Cherry Grand Prix GTP Supercharged & Intercooled
12.084 @ 114.38 w/1.743 60', 315.6whp, Fastest Stock Cam M90 GTP!
NOW XP CAMMED, 340.6whp with XP, stock heads, Gen 3 M90, 11.984 @ 115.84 w/1.750 60'!
Most HP Stock Heads Gen 3 M90 GTP!
2004 Red Monte SS Supercharged K&N|3.4 Pulley|1.9'*|180*stat|41919 plugs|3" dp|No cat/ubend|DHP|Shift Kit. 14.2 @ 98
GOT BOOST??? Friends dont let friends drive stock!