Energy C5 or C500

The 500's are the replacement for the 5's but my research is telling me they are actually a downgrade.
I can only audition the 5's, so I can't compare for myself.
The 5's are used but perfect and $75 cheaper.
Can you clue me in on stregnths and weaknesses of both?
I have an Onkyo 805 (130wt) so power is not a problem.
Thanks much.
How much specifically are the 5's? You can get C-500s from Audio Advisor and elsewhere for around $400/pair.

I heard the C-5s long ago, but haven't heard the C-500s. Many of the specs of the two models are very similar--frequency range, driver complement and sizes, cabinet dimensions and weight, and sensitivity. The biggest difference I noticed is that the C-5 has a single large diameter port on the front while the C-500 has two smaller dia. ports on the rear. That would change the room placement flexibility, the amount of rear wall bass reinforcement, and--depending on how those twin ports are tuned--the loading and damping.

Energy claims more dynamics, speed, and slam over the old model. Evolution in driver design and performance could easily account for this.

I'm not sure why you're saying the C-5's are reputedly better. In my experience, API speakers don't change models unless they display significant improvements over the predecessors. I own four generations of Mirage speakers that reinforce my perception.
Yes, I saw those 500's at AA, the used 5's are $350 and no shipping cause a reord store in town has em.
I know that isn't a good enough discount for used, if they are basically equal speakers.
I read a few posts that said the 5's were a better speaker and the 500's were lighter and cheaper....cheaper in price compared when new.
Anyone know both of these and have advice to give?
Thanks for your input Johnny.
The 500s are not significantly lighter. Here are the specs for the C-5. They weigh 47 lbs. each. Here are the specs for the C-500. They weigh 44.1 lbs. each. Just the use of a lighter, more efficient magnet could account for the difference and would signify an improvement. Also, a more sophisticated form of internal damping could account for lower weight. Other dimensions are usually within an inch of the old model. The old C-5 used injection-molded polypropylene mid/woofers. The new model uses composite Fiberglas cones, which is probably a step up. Mirage's (same parent company) flagship speaker ($7500/pr OMD-28) is using a form of Fiberglas for its woofer cones as well.

Every time anything changes models, there's always a chorus to whine that the old model was better. It's not necessarily so. In my experience with the later generation API speakers, they have a faster, more articulate bass with more dynamics than the previous models did.
Thanks for all the info. You've been a big help!