How Do I Revert From 5.x Back to 4.x ?

Over the weekend I upgraded from 4.x to 5.x and have had problems with my computer completely freezing up, forcing me to shut down with the power switch (ouch!). Other times the computer has come to a verrry slooow crawl.

MacBook Pro Intel Core 2 Duo 2.66 GHz 4 GB
Mac OS 10.6.2

I'd like to revert back to my previous 4.x install. I have a SuperDuper clone from the day before I installed 5.x, so I can grab what I need from the external drive.

Can someone tell me what the best process would be to revert?

Should I do the following?...

Run the UnInstall application to remove 5.x
Install 4.x using the most recent 4.x .dmg installer I have saved
Copy the Parallels .plist preference files over from my external clone

Or can direct me to some online documentation that describes the steps to take?

Thanks!