Good Morning,
As Gord has mentioned above the differences between Maximizer version 5 and 8 are far too many to discuss on a forum such as this, I would suggest that you take a look at the Maximizer website here:
Maximizer.comAs you may still find some v8 material on there.
I would strongly recommend though that you suggest they reconsider an upgrade to 8 and go for 9 (if they want the pro version) or 9.5 (for enterprise) as when the next version of Maximizer comes out it is highly likely that Max 8 will be dropped from the supported products list.