I looked into the cartridge options in preparation and would have an issue using one of the roller bearing types which were up for between 150 - 260 quid.
I used the 270 and 360 non roller bearing kits years ago on my nissan 200sx and whilst prices have reduced somewhat today they seem a bargain at 25 - 50 quid I didn't get as long out of them as I wanted - getting the turbo off the nissan on my drive with the engine in situ was a proper ballache, really hard to get to the 3 downpipe bolts so was not best pleased when they failed
but the main thing before you start a turbo rebuild is make sure you understand why it failed in the first place, normally oil starvation or bad heat up / cool down cycles boiling the oil off and address that first otherwise your investment will be short lived
consider budgeting for new oil supply / return pipes at the same time (lesson learnt the expensive way)