Until the car runs well, I wouldn't even consider further mods. This car has lots of mods already, I see the bleeder valve up front, external wastegate, aftermarket downpipe - someone has already been tweaking on it. Don't throw money at it; learn from our mistakes. And please hook up the a/c. Plenty of parts guys on the board that can hook you up with the missing parts affordably. It will be hot soon.
What kind of transmission does it have? That is an odd looking dipstick in the photo.
Last question: Does it say Turbo on the air conditioning box on the firewall?