Down there, you can certainly make the case that a parallel flow condenser would be a worthwhile addition to an R-12 system. If the cost is as low as $150., I'd certainly do it. Why bother with a 20 year old condenser with unknown heat transfer capability through it's tubes??

Now, up here, I'd probably save the money.........we hit 90°F. about four or five times per year.........and 100°F usually happens every two or three years. The R-134 systems are adequate for this task, even with the old condensers.