nice wrig and beautiful rare color - love it! probably has replacement rear springs as all XJs have sagging stock leaf packs. keep the wheels - they are rare and look much better than black steel - biggest you can go is 31x10.5s on these as is (even with aftermarket rims). you might need a front spring spacer or new front springs to even out the stance out but to be honest it doesnt look that bad to me (it depends on your preference and cash flow).
before you go buying bigger tires and wheels ask yourself this:
1 - what do you want to use the car for? for everyday driving, beach work, touring, towing and mild off roading: 31s will work great without re-gearing, fender trimming, lift kits, adjustable panhards, extended brake lines (etc, etc - the list goes on and on) and is the most cost effective and the best "no extra expense" option before going bigger. anything over 32s will require a heap of mods and cash so know that now
2 - how big of tire do you really want? big tires look cool but it involves more than just a tire/rim purchase or a cheap lift kit so dont fool yourself or talk yourself into saying thats all i need (tires and rims). doesnt work that way. so do your research now
3 - are you going to be happy with 31s on a stock lift or do you think you want to go bigger later? most people want bigger later even though they dont realize it at first so thinking ahead is my best advice.
you need to decide these things now and make a long term commitment before making any purchases lest you end up doing multiple lifts and tire size changes and wasting your coin over and over. most people talk themselves into smaller tires and lifts initially but then become eager for bigger soon after. no point buying 31s now when 6-12 months from now you decide you want 33s (a big leap that involves lifts and other parts at exponential cost)
Ive seen this thinking hundreds of times and it always fails the pocketbook in the long run. dont let yourself get caught up before you have a realistic plan. you will only end up wasting a big chunk of cash later (not to mentions parts you never considered or planned for).
just my two cents. Cheers