1997 e420

[knarf]

Greetings Fellow Fourm Members,

I'm currently in the market for a newer semi beater Mercedes to replace my recently deceased 90 E300.
The 97 E420 interest me. I'd like to try a V8. I've been researching threads on this site.
Some of my questions might seem redundant.
I've been made aware of the spring perch and rust issues with the W210 but so much talk about the transmissions has me concerened, i.e. it's reliability and to change or not to change the trans fluid and filter.
The car is being offered by an independent non mercedes dealer, limited history and receipts.
The Carfax looked but I am aware of the limitations of these reports.
The price seems right.
What is the difference between the 722.625 and later 722.623 trans used in the E430? Is the latter a "better" trany?
Any advice and information would be appreciated.