Best EFI harness and ECU for LS transplant.

[7firebird1]

Hello all! I am in the process of dropping a 5.3 LS engine in my 71 Firebird.
I am in search of a good plug and play setup that works good but not overpriced. I have looked at Holley and FAST and not sure which one to go with, or maybe there is another unit I should look at. Any help would be appreciated!