Reply to Speeding Up A Set

I'm trying to piece together a 30-45 minute long DJ set starting out with Electro House (120-130 BPM) and then easing my way into Dubstep (140 Bpm). When I slow down the dubstep tracks I want to use to 130, they end up sounding distorted and just not flowing well. Are there any techniques I could use to gradually increase the speed of my set without throwing off the people on the floor dancing, or should I just look for songs that work at the same tempo?

Thanks in advance for any feedback.