XRAY - Model racing cars

Since moving from the Mi4LP i've come on leaps and bounds in terms of driving. I found that the Mi4LP wanted to push more in corners.
Where the T3 11 seems to want to understeer slightly at the beginning of the race then the front end starts to dig in approx half way through a race.
I think im overheating the front tyres though. As the rear of the car really starts to become lose.
That or the car seems to push initially and as i let off the throttle to reduce speed, the rear steps out.
I dont think that my drivings the best using a wheel, as i think sticks would yeild more control over the throttle position, so i wont blame the car entirely.

On high traction tracks i can keep the lap times consistent within 1 second of my fastest when i drive at my best, but its somewhat of a fight to maintain.
I've got H links on the front with around 1.5-2mm under the upper camber link, with 1.5 degrees all the way around. Im running 1 hole rear uprights which made a huge difference in my opinion.
I think i've got 2mm under the front steering block rods also. Oil im using 40wt.

Front shocks are in position 3, where i've got the rear ones laid all the way in at position 1.

Could anyone explain what adding spacers under the upper camber link and inbetween the shocks and the shock tower does?

Any suggestions would be greatly appreciated, other than start off with a base setup again. Im a little stumped.

It sounds like you are overheating your rear tyres. If your fronts were overheating it would push towards the end of the race, and not stop very well. It also sounds like your tyres aren't quite ready to hit the track if they don't come on until half way through the race, so maybe try a different goop or try baking them for longer. If it's on asphalt, 20 mins @ 60 deg works best, if the temps are low then try a bit longer.

To stop your tyres overheating you can try a harder tyre, softer springs, heavier shock oil, less rear toe, and also just try to be smoother on the throttle or run some -ve expo. If it's still stepping out then stand your rear shocks up.

I have had this before when overheating front tyres. To get rid of this I would run both posts in the front to reduce flex and use heavier weight shock oil to start with and see how it goes