Umm, I would like to chime in here before [MENTION=275323]bradze[/MENTION] buys seats from a limited to find they won't work in the SR5. I don't want to be a killjoy, but I want to prevent a large purchase and larger disappointment later on.
[MENTION=67802]nglayton[/MENTION] is right in that past Toyota's from the 80's, 90's and early 2000's did parts share, and to an extent they still do with certain vehicles, Prado to the 4Runner etc. He is also correct that between and base and premium trim, the difference is in the sub-harness and modules added later down the line. That being said, there are some connectors that are only on the main harness. Here is why the limited seats are a no-go.
Firstly, there are THREE different base wiring harnesses for the 5th Gen 4Runner, regardless of whether it is a premium or not. The SR5, the TRD, and the Limited. They are absolutely different, and it does matter what dash harness you have if you want to add things from other trims. Toyota did not add anything that did not need to be there for other trims. Trust me I have been trying to circumvent this problem in a few areas.
The limited seats will mount into an SR5, and you might have the power adjustments work, but you will not have heated or cooled seats. The limited seat control is off a pigtail under the HVAC control, and it is not there in the TRD or SR5 Trims, nor is the requisite dash wiring between the junction blocks to the seat connectors coming out of the floor. The limited seat frames and cushions are different too to accommodate the blower and ducting inside of them.
I will state that if you want power and heated seats in your base SR5, find an SR5 Premium. This will literally be an easy swap to do, just swap seats, and everything will work. I added the premium heated seats to my base Sr5 when I did the leather swap, and they worked.
Just wanted to provide some insight