Thanks in advance for some great knowledge learned by reading the posts of some great professionals!!

I am upgrading my home's 18 year old original Furnace and AC system that has finally deteriorated. With this I am trying to improve my systems air filtration/purification ability as pollen and air particulates have caused some health issues with my family.
I have a few bids from contractors to install a Lennox el296v and 13acx AC unit. I am looking at adding a HC16 or Pureair to the system. My question is the benefit of the cost of the Pureair over the hc16 - is it worth it? Anything else I should be considering?
Any other recommendations/tips would be greatly appreciated as well.

The house is 2250SF, two story and we are in the West with minimal fairly consistent temperature climate (low's 30 in winter/high 95 or so in winter with minimal humidity). House has 13 registers and one return in the upstairs.

Thanks again to all !