I did this job on Saturday on my 159. The most difficult parts were:
Removing the hub nut, which is very tight, involved me standing and bouncing on a long 1/2" drive breaker bar with a bit of an extension on the end for more torque.
Getting the old hub/bearing assembly off, its a tight fit and gets corroded to make things more difficult, a chisel and a big hammer did the job, took a good 15mins+ of bashing though.
As far as tools go, you will need a 36mm socket, I read in a lot of places that it needed to be thin walled and the cheapest I could find was £15. However I'm not so sure about that now so you could probably get a normal one for about £8.
You also need an E14 (star shape) socket for the 4 securing hub bolts, and as mentioned previously a puller is useful, in my case all it did was push the driveshaft out of the hub.