They are a bit of a pain tbh, mostly due to the stupid way the rear arm is assembled.
The inner bolt is put in from the rear by the factory so you're supposed to drop the subframe to get to it. What most people do is cut the head of it off and push it in to the subframe, and put the new bolt in backwards from inside the subframe.
The outer balljoint is a complete pig to get loose on the aluminium uprights because its blocked by the CV joint. If you have steel uprights (PF or FL with 20") then a solid whack on the outside of the taper with a hammer is usually enough to pop the joint loose, but that doesn't work on the aluminium ones as they have a steel insert to form the taper. I've not yet found a balljoint splitter that will fit round the chunky uprights and so the best way (I've found) to get them out is to remove the CV joint from the upright so you can get a socket and extension bar square on the nut and then beat it out with a lump hammer. Often the balljoint is seized in the tapered insert so so the insert comes out of the upright with the arm. You then need a bearing puller to get the insert off which you can hammer back in to the strut.
The front arm is relatively straightforward by comparison, but bear in mind its supporting the whole weight of the upright and brake assembly on the suspension strut so when you remove it take care to support the brake disc otherwise it will drop and tear the upper bushes apart. Its also worth doing the ARB links while you're at it, since you have to take them off to get the front arm off anyway.
Lemforder / TRW are OEM, but if you have factory 20" wheels the only option now is Meyle HD as the genuine ones are NLA from TRW.
I have Meyle HD on mine and they're working nicely so far, although I on;y have about 12K on them. Murray's Direct on ebay is has been the vendor of choice for Meyle, although there are a few others now with slightly better pricing. Meyle have an online catalogue so you can find part numbers from that and then put them in to ebay and see who has the best price. The nice thing about Meyle arms is they come with all new hardware which makes everything nicer to reassemble, especially if you've cut the heads off the rear bolts
