I just had one done on the rear of my 300 tdi it cost £74 inc VAT, if that helps, normaly do my own, but did not have time this time and wanted the Disco back on the road, it so easy jsut a bit of a pain and dirty.
Dont worry about the E20 torx socket, if you got a two hex 13mm socket it does the job, keep your old races and gut a grove in them then you can use the next time.
Have a look at Busters Guides, these are agreat help.
Go for it, the kit will only cost you about £20 to £25, do both sides as well, cuase the other will not be far behind, and you only spent £50, you can spend the rest on tools to save ya more money, and give that great feeling that you done somthing....