well one thing, i dont really care much about gas mileage, if the car is tuned and working correctly, 25mpg isnt bad for a performance engine. before I took the 195 temp stat out, my car ran at 220 degrees all the time, it made it feel kind of sluggish. with the 180 it definately runs alot cooler and responsive. maybe im crazy "uhhhh yeah", but I feel the difference. not to mention it is a requirement for most performance chips. Ive tested superchips, jet chips is next. free flowing exhaust, 180 temp stat, and use of 91+ octane fuel are the base requirements. as for others opinions, its just that, this is a message board and most people will reply based on experiences they've had themselves, not professional advice. I know alot about my z34 cuz I've done most of the work, so I toss my experiences toward helping others. never take someones word on a message board as gold. find yourself a trusted mechanic and keep with him/her. the more one shop works on your car, the better your chances the repairs are done right, simply cuz they are learning more about your car as you go...