Alrighty, did the thermostat today, as well as managing the fuel pump and filter. Did spark plugs as well but they weren't needed.
Nonetheless, the thermo was stuffed, didn't open after i put it in boiled water haha, new one seems to work fine but haven't taken it for a drive, on idle it never went above 1/3
We noticed a bit of an air leak - probably from when I intalled the MACE TB, I didn't seal it, so we got some sealant out and did both the TB and plenum but it made it a little worse :/
Only other thing at the moment is a tiny coolant leak at the thermostat, I'm guessing it was pretty average gasket sealant