the best way to find out if the plugins are universal is to just check with the company. if your plugins are fairly recent, most of the universals are free updates. if they are a little older, then you may be looking at paying for upgrades. if the effects have been purchased by another company (like image lounge, acquired by red giant), then they may not be available yet. some effects (like the freebee pete’s plugins) may never be available as universals.
another thing you want to have are universal codecs. if you only have a ppc version codec, you won’t be able to read those files on the intel macs (or write to that codec), so make sure you can get any important codecs as universals.
i have taken project files from intel to ppc macs and the other way around, and have had no other issues except an occasional missing plugin on the intel side and once a non-universal codec issue (which was an easy download to fix).
note, if you really need a non-universal effect or codec, you can set ae to run as ppc to get those effects or codecs. you can do this by selecting the application, then choosing file>get info, there is a check box in that panel to tell it to run under ppc emulation (rosetta). i would assume the problems that were encountered running ae7 on intel macs will probably be encountered running cs3 this way…
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW