What year SR5? 88-89 have carbed 4AF motors, 90-91 have the EFI 4AFE motors... go with a 90-91 if you can as they have a little more power than the 4AF.
Not much I can think really as I have a GTS, there are rust problems but they're more prone to the northern states and Canada where road salt is used. The motors are pretty much bullet proof with good maintenance.
Coupes tend to leak from around the headlights, and the sunroof motors seem to die. Also the headlight motors don't last forever.
I'm sure some of the SR5 guys will chime in.