http://highperformancehvac.com/trane...-conditioners/
You seem to recognize value.
Coated coils is an option no matter which brand is selected.
However, TRANE has the reputation of more effectively addressing condenser life in adverse conditions over a long period.
Post # 8 ... I would not increase the unit size if the current 3.5 ton system can provide 75'F on a 94'F day.
................. I can not provide specific specific selection without "seeing" your house or recognizing all appropriate factors are addressed in a reasonable manner.
I am not sure if Returns in all bedrooms is requirement for
existing houses.
I need to read the specific section of the FL Building Code and energy efficiency requirements myself.
This requirement has been in effect for NEW Construction for about 8 years.