+25 should work just fine.
I'm not sure about your mudflaps; those are usually the first things you have to take off because they're so thick, but try it and see. There's a couple good aftermarket options now though.
These are shipped from Japan, landing on the west coast. Trains are slow, so expect the late end of the window. My estimates were 12/19-1/3. It got delivered to the dealer on 12/31.
Since you're using the same tires, the only change would be coming from wheel offsets. What you're running right now (+19.6 with the spacer) is slightly more tucked, but very close to +18. You really just need to see a +0 to compare.
-24 offset is pretty far out, literally.
You're gonna need the lift kit at least, and you might need to trim some stuff/remove the crash bar, since your front tires will move forward/backward more when you turn with these.
Edit: Oh, and our stock centerbore is 95.1 cm; you might need a...
Pretty sure our engine has port injection as well as direct. Catch cans have benefits other than keeping carbon off your intake valves though.
I'm interested in the answer to Vicenzo's question...
Also @SXTH Element, knowledgeable people need to see the inside of the can before we buy.
I'm not sure if you have your 4Runner yet, but if you don't and you decide to go this direction, it's important that you try to take the route @Scrappopatamus did and order the vehicle with the regular OE wheels, buy the TRD ones later, and swap them.
I was forced into the upgrade TRD wheels...
A lot of people have weighed in on the other stuff, but I wanted to comment on this: Yes, it depends on the dealer, but you have to understand up front that the "ToyotaCare" free maintenance only consists of oil changes every 10k miles and tire rotations every 5k, up to 25-30k miles.
Some...
Seconding this.
That said, it looks way better, and is probably how Toyota should've designed/made them in the first place. I'd be wary about the quality of the paint job here though...