I like the mantec and am using it on my 110. On my 90, I wanted something with Jerry cans as well, so I welded my own. What I suggest (strongly) is use the truck for a while and think hard and realistically on HOW you are intending to use it. There are a lot of folks that buy one with the intention of off roading it in the mind's eye and/or overlanding or whatnot, but that is a vision of who they may like to be and not who they actually are (or are logistically not located in a place that would allow such things). Others just friggin love the look and want to have the truck whether garage queen, grocery getter or just image maker. And some love to offroad... So think on how you really want and intend to use the truck for a while before doing anything! That will go a long way in the future on redoing early mistakes that I guarantee you we have all been through when we first got one.
Lift kits ruin geometry if you are planning to stay on road. Hell, they kill it for off road too--it isn't about vehicle "height" as your axles don't raise up unless you run larger tires. Running larger tires can stress smaller engines (like 19J, 200/300 TDI's...) and changing gears to accommodate hurts your overall speed. Things multiply as you can correct geometry, gearing, suspension... but it is not done by guessing and it gets intricate and potentially expensive.
So in regards specifically to a spare tire carrier, I would first determine if you are sticking with your tire size so that you can get a carrier that can accommodate whatever size you want. It would also be helpful if you knew if you were going to need any jerry cans and or highlift mountings for it. So USE the truck for a while, toss the spare in the back for now but make sure you have adequate tire-changing equipment in the truck such as an adequate jack, socket and breaker bar.
And if you are intending on off roading, even experimenting, make sure you bring some recovery gear. My only mod that i would do at this stage is to make sure you have a front recovery point, even Jate Rings on the front chassis horns at a minimum. Don't ever use your ball on the back--use the pin. You may know all that already.
Change just what is absolutely necessary. Use any income on gas as you use the crap out of the truck. My only fixes right now would be to clean up any rust spots enough to slow things to a crawl in that regards until you have some time under your seat
It is a FINE truck! Enjoy and don't be a stranger! If you do any fun upgrades, take photos and share your progress! If you do any wiring, take pictures and more pictures and make sure you document what you are disconnecting from where... Go to landroverweb.com and download a manual. Use it first to become familiar with basic procedures then fire off your questions here!
So happy for you.