You may have a little problem if your Mustang is an '05 V6 with the throttle body heater. (You can tell if you have the heated TB by looking under the TB, do you see 2 hoses running to a block under it? If so you have the heated TB) If you do, then contact the seller before you buy. There was a problem with the clearance between the upper radiator hose/t-stat housing and the heater block. (I have this problem). The quick fix, and the one I am using, is to use the aluminum box and the original plastic t-stat housing. Works great, and no clearance issues. I seem to remember the seller has since fixed the problem, but I'd check and make sure. I've been running mine for the last 2 years, and it works great! No problems at all.