I run the Losi clutch. I was running 4 aluminum shoes with 2 silver and 2 gold springs. It hit hard on the bottom but my clutches weren't lasting very long due to how heavy of a spring setup I was using. I just tried 2 aluminum and 2 carbon shoes with 2 gold and 2 green springs. I have to say I didn't notice a difference on the bottom end on my full mod. It still hits hard (I like a lot of bottom end punch) and it seemed like I had more top end speed because my clutch wasen't slipping at the top end due to the lighter springs. If your bottom end is a little "soft", your tune may be off just a tad.