Offroadrules15

Here it goes. I have just acquired a lq9 with stock bottom end, patriot heads, cam (specs unknown), stock intake manifold and a BBK 90mm throttle body. This engine was built in 2005 by a company that is no longer in business and was set up without MAF and O2 sensors. It has a MEFI computer and supposedly was built to 500hp at the crank. The reason why the previous owner sold it was because they put more weight in the desert truck and was now under power. He did mention that sometimes it ran great and other times it ran like crap. Just before he sold it to me, he put it on the dyno (at a very reputable race engine builder) to try to get as much power as possible out of it and the builder said that the MEFI is very outdated and by using a newer style EFI system could greatly improve the performance of the motor.
In the past I have had Lq9s and L92s. Both, I used O2 sensors and a MAF. I am debating on whether to scrap the MEFI system and put on more of a stock set up (O2 sensor and MAF) or go with the FAST EZ EFI 2.0.

What do you all think? I have budgeted $1500 to get this motor running at its best.
Note* this will be going in a desert truck that will not be used for street or racing use.