Well, to add variety and to sync, learn how to speed up and slow down replays. Right click on a clip, go to Insert Envelope and click on Velocity. A green bar will appear across it. You can move it up to speed up the whole replay and down to slow it down. To speed up certain bits, double click somewhere on the line and a blob will appear. Then make another blob at the point where you want it to change back to normal. In the middle of those two green blobs, make a third and move it up and down to create the effect. Don't go into minus numbers otherwised your replay will go backwards. You can move the blobs up, down and along the replays. Fiddle around with it a bit ;)