but going to napa would mean getting a aftermarket radiator, right? which means it would not have the cooling capabilities. Maybe im wrong because i dont shop at napa much
Yep, it's all aftermarket now, and nobody in the aftermarket has tooled up to make the 40mm core SVT/ST220 radiator, so I'm afraid we're all stuck with a 26mm core radiator unless you're lucky enough to find an SVT radiator in a junk yard, and you have to take into consideration that the youngest of these is going to be 16 years old, so you'd be installing a very used radiator.
SVT Contour radiators are not easy to change, so were I you, I'd want to install something new with a warranty, even if it wasn't the thick core OEM part, which is Unobtanium anyway.
The SVT Contour cooling system was designed to cope with its 140 MPH sustained top speed, and I know the Roush employee who was the principal calibration engineer for this car. He lapped an SVT Contour on Ford's Arizona Proving Ground oval track at 140 MPH, long enough to empty the gas tank several times, and if you're regularly doing this, you probably need the 40mm core radiator, but as others have pointed out, the 1" core radiator will serve you just fine.
Suggestion: While you have the radiator out, clean the 100,000+ miles of accumulated road crap out of the A/C condenser, you will be amazed at how much debris is caught in the fins of the A/C condenser, and this is blocking airflow through the condenser and the radiator which sits behind it. I use a garden hose and nozzle to spray water backwards through the A/C condenser. Don't use a pressure washer, it will bend over the fins.