I have a 2005DE I can go from service to service without burning a drop it would bother me big time if it burnt oil at that rate .definitely try to get to the bottom of it change the valve as said above . How many miles has it covered ?
Revving the engine high with no load on it is not something I'd recommend . Chances are you have loosened some carbon and soot from inside the exhaust.
It's down to how you're going about job .l would try siting a new nut on the broken stud filling the hole in the middle with a mig welder the heat from welding on to the stud will melt eny thread lock that may have been used. Screw out with a ratchet and socket I've removed loads of broken bolts this way.
Late 80s and just about all of the 90s me my brother and just about everybody else used to swap cars that's how I got into nissans my brother swaped his golf gti for silvia turbo.
forgot to add sometimes this was on a weekly basis
it happens unfortunately if the box isn't that common prices for individual parts can cost a fortune .if it were a vectra or a mondeo the gearbox guy would hand you one off his shelf .
I would have a look at the inside faces of all the discs .
Only doing 30 miles or so a week the pads could be jamming up in the caliper .outside faces of the brake disc s always look much better than the inside.
Your old brakes wher obviously working fine the garage have replaced them probably because the pads wearing thin and excessive corrosion on the discs .
Yeah fitted a chinese android special the other day. Levels are now a bit low, but I can deal with that until I pick out and buy the rest of the system.
check out the buster mod for sorting out the low levels.