Both have fuel return systems...the difference is that M4.3 have it on fuel rail and M4.4 have it at right hand rear wheel(fuel filter area).
M4.3 have FPR on fuel rail and M4.4 have fuel pressure DAMPER there...while fpr is in fuel filter area in the back of the car.

They are identified by their colour.The colour says what flow rate they have,besides Bosch part number. I don't have a turbo,but as far as i know... M4.3 & M4.4 turbo car's injectors are interchangeable. Parts stores are not quiet correct about info they provide,sometimes pretty confusing...BUT ...

If it's hydraulic tensioner...it's the only thing you actually need to remove.

It would be cheaper to replace the whole hood...from the junkyard.....if you manage to find a matching colour....it would be nice.
Headlight and side markers also from junkyard.

is there a way to delete the airbag system and bypass so the light wont show up? looking to put a momo steering wheel and a set of vdo gauges It's not my concern but...I can't understand that you want to remove a steering wheel with airbag because of MOMO sport steering wheel. Why would you risk yo...

Carefull....resistance measuring with a multimeter can lead to airbag deploy!
There is a statement about that,somewhere in Volvo SRS documents.
No measurements of any kind should be performed in SRS system.

Don't forget to reset fuel trims after timing belt re-check by disconnecting neg.batt.cable.

Wait for another 850 to show up on a junkyard and grab it.
I'm not sure about removing it completely...it acts like a safety catch if one of side ones fail....otherwise you could end up with broken hood and windshield...if it opens on the road.

Just keep the battery and pulsing away from fuel and vapors...long wires would be a MUST...and well ventilated area.

https://www.aa1car.com/library/voltage_drop_testing.htm

Voltage drop test MUST also be performed under load(headlights,rear demister and heater blower)...and on both sides..positive and negative.