I would like some opinions on a CRM system I am thinking of implementing at work.

The purpose of the system is to allow sales reps, tech support and customers (et al) communicate and maintain one location to track all correspondence. I would like any opinions business wise so far as missing features you'd suggest including and programming wise in terms of feasibility etc.

For the start of every interaction create a unique from / reply to address formatted by assetname-thread-message ie ad-0-0@domain.com being an email about an ad it is thead 0 and message 0. If the receiver of the email replies the system captures the reply and forwards it (automatically) to the necessary parties with the reply to / from as assetname-thread-message+1 so ad-0-1@domain.com and so on and so forth.

The system would offer email only options or a web panel (27 signals highrise style system).

I suppose to start with how well would or wouldn't spam filtering and email systems deal with constantly changing reply-to and from? Is there some alternative way to tag the emails that would allow me to track the asset, thread and message?

Thanks for any input