I think your right feel with the R turbo, it doesnt look like it will be worked to the same standards as jacobs. (Polish/port/thermal coated)
Maybe sending jacob a used K04 23 turbo might be a better idea to get the costs down, it would save the cost of a new k04 which is probably why its expensive.
Jabba manifold £550
Jabba IHI £1000
Jabba DP £300
Jabba TIP £150
440cc Injectors £250
Larger MAF £100
Jabba Fitting Kit (bolts gaskets/seals etc) £100
Jabba sports cat if you do not already have 1 £250
Jabba boost controller if you do not already have 1 £150
Jabba remap £475
Coolant return pipe turbo to block £60
Coolant feed pipe to turbo £60
Boost pipe from turbo to std pipe £100
About £3500 worth there
Jacobs all in will be less than 1/2 of that, although it will not be as good!
Sie needs a session at JBS to see what kind of power it is putting down @ the flywheel