First of all, Biff at V-Mania is the absolute BEST to deal with.
Secondly, his products are all top-notch! I have both his windows and his new hardtop - they are nothing but the best and he has got great prices as well!!!
Now about the windows, I have the regular windows on my 94 RT10...no sliders. I also installed the door pops which simply pop the door open with a push of a button...it is great. Never have to worry about locking the car since it is technically locked when the windows are on and the doors are closed!