My heat pump (outside condenser unit) is dying and needs replacement. Indoor air handler running fine. Both units are 10 year old Carriers. 2 questions:

1. Do I need to replace the indoor air handler unit at the same time? I know doing so would be best for efficiency, but ignoring that, is it OK to get just a new outdoor condenser unit?

2. Any thoughts on American Standard performance/reliability? Was quoted $3200 for the 13 SEER 2 ton unit, including labor. Northern Virginia.

Thanks everyone!
-Tony