Last day to order 2020 is 3 APR 2020.
Looks like 14 week leadtime for 2021s, so if you order on 13 APR, you will get it around end of July/early August.
On the pre-2020s, if you get the 2.3L AWD, everything will be fine except your roof rails may pop up at the rear, door panels might be misaligned, and your hood might corrode. The 2.3L uses a different PTU than the 3.5/3.7 so you won't get the overheating issue. If I had to do it again, I'd have gotten the 2.3L engine with AWD. Plus you can tune that 2.3 to produce about 380 hp, whereas the N/A 3.5 is stuck at about 315-320 hp tuned (maybe up to 340 hp with ported manifolds). The 2.3 and 2.7/3.0 EcoBoost engines all use external water pumps. The 2.7 Transverse is 99% the same as the pickup truck engine, and the 3.0 on the 2020 ST is basically the same as the ones used on the Lincolns. The 3.0 can be tuned to around 550 hp. On the 4800 lb 2020 ST, that 550 hp basically translates to low 12s, same as a tuned Fusion Sport which is 700 lb lighter.