When installing a new A/C compressor is it proper to install new line sets? Actual age of existing lines is +/-21 years.

What is the consensus on Freon vs. Pureon based systems?

What size coil should be used for a 4-ton capacity A/C compressor?

Looking for feedback (quality etc.) on American Standard-brand A/C Compressor (4-ton 12-Seer)and Freedom 80 gas furnace.