It is relatively complicated. On the front you have the hub, which at the top has a top wishbone, at the bottom is the Balljoint, the main suspension arm and the trailing suspension arm. At the rear you have a top wishbone, two main bottom arms, and a trailing link. Plus there are the arb drop links front and rear which tend to rust to the point they are destroyed if changing the arm they are connected to. The rear hubs have bushes in them, which if they wear out, needs the whole hub changing. None of the bushes themselves are replaceable (not sure on poly aftermarket ones though) so it always the case that it is an arm that needs changing. None of which are cheap from lexus. The two trailing bottom arms were something like £180 each including LOC discount. There are aftermarker arms, by blueprint I think, but I didn't have the time to search last time. I needed to get the arms couriered to the garage asap. Top wishbones are about £80'ish on ebay, all the bottom rear arms I got from a breaker, £100 for all four.
As far as labour goes, there are some hidden costs that may bite. For starters, the trailing arms on the front suspension require the front subframe to be dropped a couple of inches to get them off, so extra manhours there. On top of that, on mine, the adjuster bolts were seized solid, so had to be heated/cut/ground to get them off, time consuming. Other stuff is a doddle to do, the front top wishbones can be changed with relatively basic tools (including a balljoint splitter - see my tutorial in my sig), so not all bad :)