Does it really needs a sprung or floating guide - or is the problem that the guide is currently at the wrong height?
With many types of car a guide at the correct fixed height (for the type of track you are using) works better that a sprung or floating guide. That may or may not hold true for your car and track, but it's worth experimenting with adjusting the guide height and seeing how that compares with a sprung or floating guide.
With many types of car a guide at the correct fixed height (for the type of track you are using) works better that a sprung or floating guide. That may or may not hold true for your car and track, but it's worth experimenting with adjusting the guide height and seeing how that compares with a sprung or floating guide.