These are the parts and fasteners you'll need. I would call it fastener removal. I personally would re-install the fasteners with some thread sealer as well so they fill back in the empty holes. Maybe 30 minutes of work?
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To fit 37s it's my understanding that you'll need to remove the frame support braces on the front body mounts and the front bumper inner fender liner trim pieces and depending on tire and wheel offset some plastic trimming. That's what it takes on the 2024 Tacoma. I think the LC250 is similar. I don't think you would need anything else to run the Rubicon. I did it twice in my 5th gen 4Runner with around 2" lift and 34" tires with rear bumper protection, but stock front bumper. Stock front bumper on the 5th gen 4R was not an issue at all. Plenty of clearance, no "viper cut" or anything like that - full bumper skin. I don't really understand the viper cut to be honest. It doesn't do anything meaningful for bumper clearance I can tell, but it exposes a bunch of stuff inside to rock strikes. In my estimate that's a mod that actively makes it worse - a lot like bolting on 1,000lbs of unnecessary farkle. The LC250 bumpers are relatively high and tight. I think it's about a dozen total fasteners you'll need to remove. That plus the tires and maybe wheels if they won't mount the 37's on an 8" wheel (not sure what width the OEM wheels are). I think you'd probably cruise through on something like a 285/75/18 as well and that would probably only require the bracket removal and none of the fender trim parts or aftermarket wheels. Edit: There are some 37x11.5 tires available that would probably not require plastic trimming and would fit on OEM wheels.
What you do need is skid plates and rock rails - ideally with bump outs. LC250 comes with adequate rock rails although no bump outs. The first corner of cadillac hill on the upward direction will be the challenging spot without em, but it's doable. I've done it. I did it once with bump outs and once without. I also did it once with stock OEM steel skid plates and once with aftermarket. The only place that the OEM skid plates on the 4Runner were inadequate for that trail on a single trip basis was the gas tank skid. I would buy or make some for an LC250, but the OEM ones would do for a trip or two. I've actually been wanting to try FRP composite and steel combo skids so that's what I'd do - OEM skids with about 1/8" thick high e-glass layup on the inside for extra stiffness, lighter weight, OEM fit, steel surface for superior puncture and low friction. But I'd tell my friends to go buy some aftermarket skids.
As a comparison an LC100 on 35s with ARB bumpers took a pretty heavy beating including damaging both front fenders and I think both rear quarter panels from pushing the ARB bumpers back into the body work. In general the steel bumpers like an ARB make it worse, not better in that type of terrain because they stick out quite a bit further than stock. The high clearance steel bumpers probably have some additional benefit, but I didn't have any issues with the OEM front. Rear bumper really does - needs some sort of skid on 34" tires. On 37s though - I just don't think a rear bumper is necessary. I don't think you'd have any contact anywhere on that particular trail if you're a good driver. If you added some lift or even air helper springs for $150 - then you could just jack that rear end up in the few places you need to clear the rocks without too much fuss.
LX with AHC can lift up a good bit too. If you had AHC on a LC250 it would be fantastic. But the LX is just starting with some really low hanging plastics and maxes out with 34" tires unless you want to start cutting and re-shaping firewall and other stuff to fit comparable tires. The difference between 34 and 37" tires makes a lot of difference on what you'll need everywhere else. On the GX - that front bumper is a big liability. 37's plus lift might be enough height to cruise through that type of trail without an aftermarket front bumper, but I don't know. It's a pretty long snout hanging out there.