it might be a good idea simply to ignore the fact that you are seemingly slow at the moment and just go onlne and drive a few laps with the gti on bl1 (might be hard to find a good server for that combination these days) i and lost of other people did their best laptimes while following some other faster driver
ive given this speech a few times before and to my astonishment neither tristan or ian has tried to jump and strangle me for it yet ...
anyway ... to me the besst way of lerning how to gain control over the rwds in lfs is to delibaretly loose the rear end while cornering and trying to keep it steady while going sideways round the corner (also know as drifting best place to practice is the carpark ... try the dfp 900° mode setups you can find on setupfield)
what this will teach you is how to control the movements of the car with countersteering and with the loud pedal (its even better if you own a fdfp because you also lean to be very smooth while drifting the car)
i always though the xrg and expecially the xrt were impossible to handle ... after a few days of practicing on in the car park (as somebody already mentions dont drive too long on one car/track combo ... drive a while then stop let the new thing you learned settle for a while then go back) i started to get that strange feeling that the car actually had too much grip to loose the rear end
now a few weeks later ive even impressed a friend of mine who has years even decades more sim expierence than me with some countersteers in the fo8
but i still like to go back to that xrt in the carpark every now and then after ive spun out in the fo8 or one of the gtrs to remind me of how to do it right