aMaff said:It's not necessary, but if you're using them for performance and not looks, it's definately a big plus. Most speed shops (like GTE) have the scales there. As it's time intensive, it's generally not cheap.
I will most likely get this done as I really want to do a couple autocross events this year. It is one of those things I have always wanted to do but never find the time but I really am going to make time this year!