You state that your current system is undersized. An undersized system would run constantly at your design temperature and probably never reach temperature. Yet, you state that your proposed (larger) system will 'run longer' and produce higher (in heating) and lower (in cooling) temperatures. Can you elaborate as to what the heat calc stated as your heat loss/gain, and rating of your present equipment? Many original (older) installations were oversized, with undersized ductwork.

Has the company evaluated your duct system which could be largely responsible for your 'discomfort'.

FYI: a variable speed blower is very nice. It probably contributes about 1 SEER point.

The duct system is completely inadequate and will be replaced as well. The current system is an 8 SEER, 3.5 tons, and the strip is a whole 20kw. I do not have the calcs with me. Right now the system runs all day in winter and pretty much in summer to maintain 70 degrees. I do not know what it will be set at I am sure the ladies would like it warmer than 70 in winter and cooler in the summer but they are not paying the bill. The space is 2000+ sq ft.

I should have said the current system runs all day and hardly ever reaches temp in the summer and I would almost say never reaches temp in winter.

Here are several calculators to try out:

http://sagoro.wrightsoft.com/Carrier/Default.aspx
http://www.hvacopcost.com/

The second one can be enhanced if you lookup cooling and heating degree days for your location. Try this website to do this: http://www.degreedays.net/

Well it turns out none of these guys that quoted me actualy did a Manual J. So far I cannot find anyone local that does.

Did any of them comment on the duct system?

They all felt the ductwork needed gutted, new main trunk, new high velocity vents (for the 10 foot ceiling) and so on

Thanks for that degree day link. Last weekend, it seemed to me that it was way too difficult to find a convenient source.