What are your must-have upgrades?
For me #1 was the over-the-top 4KW Audio/NAV Install - but that's a given with my background. The stock audio system was piss-poor at best.
Stock Sized BFG AT Tires and Bilstein 5100's made my SR5 ride so much better IMNSHO. Swapped these on after a month or so of dealing with the overly soft SR5 shocks and awful stock tires. Handles better, feels more sturdy, and is more capable when needed. The tires and 1.25" wheel spacers with the 17" SR5 wheels make it look a lot more aggressive than stock - I currently have no plans on upgrading wheels.
If you want to get more aggressive with your off-roading (the 4x4 T4R is already very capable with some descent tires), then an actual lift and sliders should be considered. It's all about your specific application and what's really important to you (Audio is ALWAYS tops on my list).
Deadening the doors also gives a T4R a much more convincing "Chunk" when closing the door. I was a little shocked how a stock T4R's door sounds when closing it - same for the hood (has a tinny tone - sounds awful!). A heaping helping of Dynamat Extreme or similar will make the door sound and feel like a high-end Mercedes

Of course, this is generally part of the Audio System installation, but I would do this even if I was using the stock stereo. Tin-can doors really put me off when they aren't deadened. They sound incredibly cheap on a $40K vehicle IMNSHO.
TechStream mods - Either buy the cable or have your dealer set it up how you like it. I had the keypad linked to the windows/moonroof roll-down for hot Summer days as I approach the truck, disabled the horn when arming/disarming the alarm (don't need Techstream for this), increased rear-wiper intermittent duration to 5-seconds (no brainer IMO), killed the Seat-belt chime, killed the "auto-unlock-in-park" feature, and lengthened the interior courtesy lighting to 30 seconds.
If you have any aftermarket accessories with wires hanging out of the glove box or Aux Port - consider hard-wiring them to the fuse box. Cleans up clutter and makes the interior look so much better IMO.
Interior LED upgrades - Maybe, maybe not. I'm on the fence with mine - they are brighter but I'd like them to be a bit warmer color temp.
H9 + 9011HIR headlight upgrades. The low-beam Phillips H9's are under $15/pair shipped, and make a noticeable difference in low-beam output and offer a whiter light. Still haven't done the high-beam swap yet (and hardly ever use high-beams).
Those were my sore-spots - My T4R is now very close to the perfect vehicle

(TRD Supercharger will make it perfect

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