Timeline do's and don'ts

We have Premier CS3 on an Intel Quad Core MacPro and a Kona 3 card. We have the 6.0 Kona drivers with the Adobe plugins. What are the rules for adding clips to the timeline in Premier (we are primarily a FCP shop)?

If we have a 720 x 480 DV sequence and we drag in a PhotoJPEG 720 x 486 stock clip, should we expect it to play out of the Kona card, or should we convert it to DVCPro first? What about other formats like H264? Just drag 'em all in, or convert first (we always convert first for FCP).

Also, we almost exclusively use aiff files in FCP, so can we use wave files in Premier without any issue?

Just want to be sure we get our ducks in a row with Premier CS3.

Finally, considering we have the Kona 3 and running Leopard, is CS4 a highly recommended upgrade for use with the Kona or should we wait to install it?

Thanks.

Rich Rubasch
Tilt Media Inc.
Video Production and Post
Owner/President/Editor/Designer/Animator