I've been trying to solve some engine issues for a while. The car drives decent overall but I have some symptoms that are bothersome.

1jzgte VVTI - stock jdm 1jz ecu - obd1 car - w58 - FMIC - generic k&n style air intake - stock BOV - Walbro 450 - 12v fuel ecu mod w/ relay

I have misfire that's most obvious on acceleration in lower gears - drives fine at higher speeds
Significant hesitation when shifting 1-2 or 2-3
Steady idle for the most part but will randomly fall and remain low until restarting the car
Fuel economy is not near what it should be
Car was recently smogged and had the worst hydrocarbon rating to still pass. All others were fine, NOx is getting up there.
Stored codes are 42 - 'VSS Signal' and 47 - 'Sub Throttle Position Sensor' (not being used). Don't care about this unless its relevant which I don't think they are.

I've gone through several sets of plugs at various gaps
Replaced coilpacks and boots with another oem set
Cleaned the MAF
Replaced forward O2 sensor
Checked thoroughly for vacuum leaks
Near perfect compression test results
TPS professionally calibrated
Inspected ECU board for damage

I'm looking at the injectors next but that's more time and money for what may or may not fix the problem and they're not cheap to have cleaned. Most people just suggest I go standalone and forget about trying to replace and hope with all the various parts that could be at fault.
So my question is should I cough up the money to go standalone when I don't really have any performance goals above stock and I just want this thing to run the way it's supposed to? Are there any piggyback options I should consider? Would a wideband alone help me diagnose what's going on? Any suggestions beyond what I've done that are cheap to troubleshoot?

Thanks for reading - here's some pics for your time.

 

 

All voltage and resistance checks out. They are stock injectors - obviously the fuel pump is overkill but I had it and thought the stock FPR would keep me from spitting extra fuel, probably need to check the rail pressure. I did have the misfires before with a knockoff 255lph pump however. Thanks.