Eliminating a bypass duct if going from a 1-stage system to a 2-stage unit?

Hi. I have a single stage compressor HVAC system for my 2 story 2368 sq ft. house with a 2 zone, 2 thermostat system here in Texas. I am thinking of replacing the existing system as it is 13.5 years old. When my existing system was placed a bypass duct was installed. I am considering a 2-stage system. I have gotten several quotes and some companies want to keep the bypass duct that is already there including reusing the old dampers and other companies want to eliminate the bypass duct, install new dampers, and lower the static pressure by bleeding air into the "closed zones". Which method is better to reduce the static pressure and have a better performing system? I don't know which system would be best. Thank you.

source https://hvac-talk.com/vbb/threads/2235464-Eliminating-a-bypass-duct-if-going-from-a-1-stage-system-to-a-2-stage-unit?goto=newpost