sorry, no first hand knowledge to add...but i do have a point of view...which is...
Being an SR5'r myself, i take interest in how many guys take a 'simple' SR5, and will mod it to the same extent as folks who have TE's or LE's...right up to, and including TRDPro level. And then use them for the exact same level off-roading. Sure you can get an Air rear locker if you really need it, and some have. But Many of our forum members have taken their SR5s and made them into similarly capable beasts of burden just like the TE owners. And why not. The chassis is the same, the same V6 engine, the body is the same, the wheels are interchangable, the 4WD system is the same, and the DAC is just a more restricted version of the TE's crawl control (which many have also claimed is an unnecessary inclusion). Take away the hood scoop and what do you have? an SR5 with a little better angles front and rear. And we dont hear those guys complaining 'aw man, my mod'd SR5 couldnt take it, i need to UPgrade to a trail'. Yes, the KDSS is a nice addition, but if you are mod'ing, then that doesnt matter as much.
As i have said in other posts, Toyo has given us an excellent package no matter what trim you choose. Choosing an SR5 simply gives you a blank canvas to start your own masterpiece.
just look at builds like the one itsdchz has posted...an SR5 w/ 3rd row, yet with some additions, you couldnt tell that it wasnt a TRDPro without a trained eye...and i am sure he is going to use this tool in the very same manor. and this is a guy coming from a very well mod'd FJ.
hope you choose wisely...and enjoy whatever you select.