I would suggest that you look into mini-split heat pumps. Much higher efficiency and likely quieter. Merv 16 filtration while an excellent filter has a whole lot of pressure drop across the filter. You may need a much higher horsepower fan to deliver the air across that filter. I am not saying it cannot be done. I do not know Unico's specs on the AH, but would suggest you ask how a mere 11 or 12 might impact the size of the fan.

Thanks... We have to go with 80% due to the location and height of the room. I have been told that the system (Variable 2 stage furnace) most likely does qualify if paired with the XR15. Also told that the IAQ is not needed with the above system as it doesn't give any benefit if not paired up with a two stage a/c unit. Also, one guy quoted an 80BTU and the other a 100BTU, not sure why they have quoted them differently?

Your Bryant furnace should operate problem free for another 5-10 years so I would not be quick to throw it away. My general advise is that if you plan to move within 5 years you should keep it. If you plan to stay in the house at least 10 more years then you most likely replacing the current furnace before you move. It then makes more sense to replace it now and get to enjoy it for the next 10+ years. I would think an 80K furnace at 95%+ efficiency would be the proper size. The AC is expensive because you are selecting the 2-stage model with the WiFi thermostat. You could drop down to the single stage. WiFi is not necessary in my opinion. Also do you need a humidifier? This can be added later if you humidity is below 40% in the winter. I highly doubt you need a 5 ton AC. It is good the contractor realizes your duct work is too small. He should be doing a load calculation rather than assuming and guessing. Do you know how much you spend on AC cooling costs? People sometimes pay a lot of extra money to go from a 13 to 16 SEER AC yet they have no idea what the annual savings will be. I recommend calculating the return on investment on the efficiency upgrade part of the HVAC expense. In many cases the pay back period is very long and not worth it.

I'm in the LA area too and I've been trying to replace my broken down 3.5 ton condenser. Unfortunately, I've been stuck doing too much research (analysis paralysis), but I've learned a lot. My house is 1430 sqft, long wall faces east and gets the hot afternoon sun, I'm on a raised foundation with crawl space, insulation R25 in attic, hardwood floors, no insulation in walls, double pane windows, built in 1952, 3 bd, 2 ba, etc. You need to get someone to do a load calculation (Manual J) which takes into account your insulation in the attic, insulation in the walls, insulation in the crawl space, sqft of windows facing east/west/south/north, sqft walls facing east/west, sqft of doors, type of floor, volume of your house, sqft of house, temperatures that you want to set inside the house in winter/summer, climate in your area, number of people in house, number of appliances, etc. All these factors determine your cooling needs in the summer and your heating needs in the winter. Or you can learn how to do this yourself at http://loadcalc.net I would guesstimate that no insulation in the attic, no insulation on the walls, no insulation under the floor, and drafty old windows probably raises your cooling needs to close to 5-tons. A 5-ton condenser and matching furnace are a lot more expensive to run/operate than a 3-ton system. I ran the numbers on my house and my cooling needs were a little over 4 tons without attic insulation and without wall insulation. I have R25 in the attic and I'm adding R15 wall insulation as I type this message and my cooling needs went down to a little under 3 tons (at 35.5k BTUs). So, my wall and attic insulation reduced my cooling needs by 1-ton (a little over 12k BTUs). I think the attic insulation makes more of a difference than the the wall insulation, so I recommend that you get that done asap. It really helps. Now, getting back to equipment. I've been following the advice on this forum not to get low end equipment. This advice has taken me in a two month quest for a reasonably priced mid-level equipment from a good company (Trane, American Standard, Rheem), but I'm having trouble finding it. The best quotes I've gotten are for Amana and Lennox. The most expensive are for Trane, AS, and Rheem. Goodman is very popular probably because of the price. They have good warranty, but the equipment is not well regarded in this forum. Almost everyone says it's better to get a great installer with low end equipment than high-end reliable equipment with a bad installer. I think I met two really bad installers and two good installers. It's a feeling, but it's hard to know for sure. Some dealers send their salesperson to talk to you, so you never meet the installer. One way to protect yourself is to get a permit. In my area, this ensures that the refrigerant level is checked to make sure it's appropriate for your system. That's all the permit does in my city. Another way to protect yourself is to qualify for rebates. The rebates from So Cal Edison require an outside inspector to inspect/test your ducts and install. The problem with rebates is that it costs more money to pay for these tests and the installers/dealers build in a markup when you try to get rebates. I got quotes with rebates from Lennox and Rheem and both were in the $9500 range with the possibility to get about $2700 in rebates. It's scary trying to qualify for the rebates because you might have to pay additional fees in repairs in order to meet the requirements of the rebates. Now that I've written a book on this topic, my advice to you is to get a load calculation done and see what your heating and cooling needs are. Figure out if it's worth getting the attic insulation to cut down on equipment size. Remember that it's more expensive to run a 5-ton system than a 3-ton system of equal SEER. Oversized equipment might cause your system to short-cycle which may be bad for the equipment. In So Cal, we really need the a/c and not the heater so much. So, matching a 5-ton a/c condenser with the right 5-ton 2000 CFM blower in a furnace will result in an oversized furnace. Your heating needs are probably 3-tons 36K BTUs without insulation, but you are putting a 100K BTU furnace in order to get the matching blower in the furnace to blow the cooling air at the right speed. Also, 3-ton equipment is cheaper than 5-ton equipment. So, the savings in equipment price and the operational savings can probably pay for your attic insulation. I'm paying $1600 to insulate all my outside walls. I insulated my attic myself using encapsulated batts from Home Depot. I might have to pay a little extra fill in some of the attic areas that I didn't do such a great job on. I'm talking to the wall insulators about doing this extra work for a small fee. I want them to blow some loose cellulose into those areas that need it. Okay, you might not have finished reading all this, but see my other posts on price and equipment. I researched 3-ton systems.