$500.00 is a very good price. However, because they look like they are in good condition doesn't mean they are. The only way to know is to take the socks off and look at the panels to ensure the myloxaine is still holding the wire to the panel tightly.
Over time the myloxaine degrades and the wires come loose from the panels which can cause buzzing and flapping sounds. When this happens they need to be repaired. The good news is that if you are handy you can do it yourself by buying the myloxaine from Magnapan from $30.00 or so and re-glue the panels yourself. Or you could send them back to Magnapan and have them do it for $200 or so a panel.
It is not a matter of if this needs to be done, but rather when. Ask the owner when they were done last. If they have never been re-glued then my guess is that they will need to be done. The average speaker needs to be re-glued every 10 years or so depending on the environment they live in.
The other good news is that the speakers are easily self serviceable, will last the owner a lifetime,as well as very open to tweaking. Replacing internal wiring, binding post, bypassing fuses, upgrading inductors and caps are all easily done by the consumer.
IMO the 2.5 as well as the 2.6 are the best of the 2 series because it has Maggie's ribbon tweeter. Granted it is a smaller version than what can be found in their 3 and 20 series but it is arguably the best tweeter design ever made. You could easily turn this already good speaker into a great speaker by tweaking the hell out of it. Your total cost afterwards would be somewhere around $300.00 on top of what you paid for the speaker. That would be around $800.00 or so, and would be the pants off of any speaker going today for $2,000 or so. IMO, a hod rod 2.5 betters the 1.6. Think of a mini 3.5 and you've got the picture.
Before you buy, however, you will need to keep in mind that you do need an amp with "balls" or current. Classe', Levenson, Bryston, ect. I prefer Classe' because the high end is so smooth and complement the tweeters. Also, make sure your room is big enough. The are bi-polar and need room to breathe. 4-6 from back wall, 3-5 from side walls, and you have to be 8-10 back to have the panels blend properly.
You can get away with less room on the side with proper sound absorbing material.
As for the low end. Placement is critical. To close to the back wall will cause cancelation, but when set up properly they will go flat down to 45hrtz. That covers low E on a double bass. A sub will get you those subteranian deep notes but it isn't necessary. However, if you can add a sub when you can since it will round things out. Also, keep in mind that most speakers under $3,000 benifit from a sub.
The major complaint with Maggies is their ability to play extremely loud. With the right amp you can get upper 90's. Low 100's can be achieved but you quickly get to their limit. So if you are a head banger these are not the speakers for you. But what you give up on volume you gain in resolution and sound stage. Very few speaker image like Maggies.
A good resource for Maggie owners can be found @
www.Audioasylum.comIf they fit the above bill and you don't mind juicing them, hell, even if you don't hot rod them, then $500 is still a great deal. Buy them now before someone else does!
Hope this helps!
Ray (been happily married to Maggie for 24 years)