if MRT uses steeda springs, then i suggest doing a search on steeda springs, there have been numerous threads about it in here, and i knew a few lengthy threads in the talk section with pictures.
and yes, any time you put stiffer springs and lower the center of gravity of the car you are going to hurt 1/4 times.... though this can be combatted by quite a few things it is a general statement. will it hurt enough to make a difference... prolly not without getting in to the competition areas.
Torinalth