i know the springs that come with the kit are too soft for my XT8 - and i didn't even have the motor, esc and batteries mounted to it yet! when i put all the electronics on it to see how the shocks held up, the truck almost bottomed out just sitting there. i ended up
getting the hard springs (it says they're for the XB8, but they're also for the XT8).
i don't have my XT8 back yet to see how they work, but i know they're heavier (more stiff). i hate using preload spacers - they take travel away! of course, i'll also have to increase the oil weight.