I was very happy to have received yesterday my P-SAIT which I intended for my p226 Legion with the curved trigger.but last night, that p226L looked at me with puppy-dog eyes and I concluded not to alter its original design.
I do have several p228s, p229s, and p220sthat could very well profit from this P-SAIT and am in the process of deciding it's recipient, however, and here is the question: should I also do an SRT since all of the aforementioned are older pieces?
Or will the SAIT suffice?
Thank you in advance for your opinion.

The SRT shortens the reset of the trigger so it doesn't have to be let out as far to reset for the next shot. It's a very noticeable difference to me. If you prefer the reset distance on your Legion over your other pistols, then I would go ahead and install a SRT in whichever pistol you choose.

Keep in mind that if your 220s are old enough to have a thinner, 8mm trigger, the SAIT won't fit in the frame.