I think in general, you should shop for tires that fall into the same general category as, or comparable to, what the OE tires that the car came with are. No lower, if only to preserve the driving/handling "feel" that you have become accustomed to having. Touring tires are very likely to give a Mustang a slightly/somewhat sluggish handling feel, more like the nothing-special FWD sedans that they're mainly intended for.
(A higher-performance tire choice would be a better match for the rest of your car than a lower-perf tire, but since going up the tire performance food chain appears to not be the case I won't go there.)
'08 GT coupe, 5M, wheels, tires, pads, fluid, a few suspension mods . . . still almost stock height
'19 WRX, 6M (hers)
'01 Maxima 20AE, 5M (spare, winter driver)