All a matter of what you need... Personally I put the XT130 struts on because you can then go down the Peugeot disc/Hilux calipers road. Very nice combo, apparently stops pretty well. =P
As for master cylinder. It all depends on what caliper you use. Best bet, match the master cylinder size to whatever you pulled it out of. If it's not far off, you should be able to get away with it. However, if the pedal goes to far (ie. to the floor) and you still ain't stopping, obviously you'll need to up the size.