Installing a RCS 2 zone system.

I'm a fairly handy person and fairly comfortable working around high and low voltage wiring. I was wondering how difficult it was to installed one of the RCS two zoned HVAC systems and dampers?

I have a newer house less than 5 years old and have done a little looking at the furnace and how it's setup. It looks like it's a basic A/C and gas heating unit. It looks like the ducting heads down into the crawlspace from the furnace. It's a downflow furnace. I haven't dug around in the crawlspace lately but I think there is one set of ducts for the upstairs and one for the main floor. These are the two zones I'd have controlled.

My two concerns are:
1. I'm sure part of the house is done with the flexible duct stuff, not sure the exact working for it. I'm not sure where these start coming out of the air handler and how hard it is to get the dampers on the ducting. I'm hoping there is a portion of the normal metal duct work I can use right off the air handler.

2. How do I figure out if I need a bypass type value where if the pressure builds up it recirculates the air. I'm concerned about this with the flexible ducting.

I'm thinking I could do the project myself and save me at least a few hundred in having someone else come and install it.