steering rack ends arent too bad to do and it aint the whole rack you do it from the wheel arches (or thats how i did mine) , basically they unsrew with a set of decent waterpump pliers or a set of stilsons(do a search and there is a thread on here somewhere how to do them) ,
when i did mine i found a website called livingston auto spares( google it ) you put your reg in and then find the steering section and search for the part called rack end, (make sure you get the right one as the later xantias had bigger ones), the ones i ordered for my hdi 110 was FTR4748 thats the part number on
http://www.livingstonautoparts.co.uk/" onclick="window.open(this.href);return false;
drop links are 2 bolts each side again some are diffrent than others (plenty of advice on here how to do them im sure) also your best to get citroen ones or ( i cant remember the name of them now begins with a l and sounds german) but the cheap ones on ebay fail quite quickly,
brakes and pads i dont know as i havent done them on a xantia,
personally id do it up and keep it