It's a very slippery slope...I would say that you could do either one without the extras and be drivable. That said, additional things to consider would be....sway bar drop kits, radius arm caster bushings, longer brake lines, and maybe most importantly...gearing. The 315's will really take a toll on the 3FE's power. You have options of either a re-gear in the axles or the 10% under drive gear kit in the transfer case to help out here.
When I got mine, a '94, the PO did the OME 2.5", caster bushings, adjustable upper trailing arms, 4.56 gears, and brake lines...running on 285's (with front and rear heavy bumpers). Although I was perfectly happy with this overall, since then, I've added/changed: 315's, sway bar drops, bump stop drops, Delta 3 radius arms & rear panhard bracket, Dobinsons 3" VT springs, Dobinsons 4-5" IMS shocks....still looking to add a front adjustable panhard bar, heavier lower rear trailing arms, 10% under drive transfer case gearing, and I think I'm "done". That said, if I come across a set of 37's that I can't pass up, I may try those too. As I added groups of parts in stages, each time I'd say to myself, "wow, I didn't know it could be this much better!"
If there's a chance that you can find someone with a 3FE powered rig close to you with larger tires to take a ride in, it may make some decisions for you on how much to add to yours. Sorry if I didn't really answer your question, but hopefully put things into perspective a bit. One note, I picked my rig up from AZ, and it was set up very well with the 285's to handle a LOT of AZ terrain...I'm on the east coast, and have added parts needed for harder core sharp rock crawling through the woods/mountains in my area.
At a minimum, if you can deal with the power, I'd say yes to either lift, but also include at least radius arm caster bushings, longer brake lines, and drop blocks for the front sway bar. Bumpers would be later on my list as you may want to save some budget for other suspension or gearing upgrades.
