Have you checked the oil level on a flat ground surface? That would be a great place to start.
Also, what does the gauge read on cold start and once warmed up? Do you see the oil pressure warning light appear?
Spend your money on suspension, tires, brakes and maintenance. Leave all of the other work until you are off your p plates.
The "grill" you've mentioned in the post above is actually apart of the aftermarket front bar.
Those viscous hubs are mechanical and engage at a certain temperature detected by the brass coil you see on the front.
ECU controls none of this.
I had an issue once when I purchased a brand new hub. It took some time before it actually started functioning correctly.
I believe there's a run in procedure you need to follow when installing the new hub. Were instructions included with your new hub?
I called it quits and found myself a near new condition R34 GTT hub which also suits the R32 fan. Genuine item and at least 10 years newer.
No issues so far. I have 3 spare genuine hubs all in working condition. If you want to go that route let me know and I can send one your way.
R32?
They'd be your power-steering lines that run in front of your condenser to keep your fluid cool. Very common that the 2 hoses that run through your radiator support start to weep and leak fluid causing your dirty oil build up.
P/N - Left hose - 49725-05U20
P/N - Right hose - 49725-05U22
OR you can just head to Supercheap auto and purchase some 10mm ID trans cooler hose and replace.