SimbaSC300

This last Saturday, I went and purchased a 3-owner 1995 SC300 with an NA-T setup and an R154 trans swap for 7 grand. It runs and drives, but roughly, it runs very rich at the moment(it burnt through its entire tank on the 90-mile drive home), it breaks up in boost, and if I try to go into boost, I shoot black smoke like a diesel. Based on what I see on the car, the aristo ECU, and the parts list, it appears that who did this followed the Ali SC3 guide but clearly messed up somewhere along the way. I included some photos of the car, a video of the engine bay and the current setup, a mod list, and a photo of the current ECU in the car. I bought this car as a project car that I would hopefully take to college in the Fall to study automotive engineering, and I'm ideally trying to get this up and running all in for under 10 grand, so I have about 3 grand more in my budget. I'm quite new to the platform and would like any input at this time as I learn the platform. I've explored the option of buying a mega squirt 3 pro-plug-and-play or an emu black ecu with a plug-and-play adapter and then taking it to Freed Engineering to get it tuned, I believe I'd be able to do this under 3k, but I wanna know what issues I may run into or if I will have to mess with the harness at all. Freed Engineering gave me a quote of 4500-5000 to do a full custom harness, install a standalone ECU, tune, and labor, but that would be the last resort. Ideally, I'd like to figure out a way to get it up and running as is for as cheap as possible, I'm 90% sure all the hardware is there it's just that something is messed up. As I'm new to the platform, if there is anything I should know, please let me know. Also, I plan on flushing all the fluids on the car, so what fluids do you guys recommend I replace them with? Also, my tachometer doesn't work, and my clutch gets hung up on like a bump or something in reverse gear so any proposed solution to those issues would be great. My only thought on why it's not running right is because the previous owner switched the ecu from a supra 6-speed gte to an aristo gte one, my concern with this is that the 2nd owner did all the install and wiring and then sold it to owner before me who gave me that mod list as is and it says that it followed the guide with a supra ecu so maybe its messed up because the slight differences in running an aristo vs a supra ecu but I have no clue why 3rd owner would've decided to switch ecus.

Tallyhoe

I'm not an expert on the 2j platform, but one thing I know from owning a modified and tuned MR2 Turbo is that turbo cars are thirsty. Especially shaddy modded ones. Eitherway, you will want to double check all maintenance items like spark plugs (check gap/condition), wires, ignitors, oxygen sensors, catalytic converter and timing, among other items. From the diesel expresion you used, it sounds like you're running rich, so I would think you're running catless, and if it's there its probably gutted. So the computer will dump more fuel since it's not getting feedback from all sensors and it's thinking it's not getting enough fuel. Timing may also impact your fueling and how much you burn.

Your budget may be adequate for basics, but can quickly add up especially for tuning. Someone with more knowledge may chime in and give you better advice.