If you have the intake I'm thinking the biggest decision is going to be which ECU.....?
When my intake was done it had injectors too small for the application installed, and the lines weren't done in a way in which I could leave on the car, the throttle bracket was made twice, once by the EFI guy and once by the engine builder, neither bracket would even work. There was no return provision for the fuel system whatsoever and somehow it was claimed it ran on a dyno. Who knows...

What I am saying is.... if I did it again I would do the intake conversion myself. No doubt about it! Nothing worse than paying to have something made, then not liking some things, some things don't work etc so you HAVE to remake things you've already (over)paid for....