Add a Subwoofer to my Vandersteen 1ce s or replace with Revel Concerta2 F36

I have bought my 3a sigs and Treo's (actually ctsooner's) used, so I don't see a problem. Actually, I bought all my equipment used either here on Agon or USAudiomart.
If you do buy used Vandy's, it would be better to get the most current model. As pointed out, the 2's have been in production since the 80's. Richard constantly upgraded them, so the latest iteration will be your best bet in terms of sound quality. So, a 2ce or 2ce sig should be what you are looking for. Vandies are pretty well built. Even if you do buy a vintage model, your dealer will be able to have them repaired, usually for not too much money.
I understand your wish to keep local dealers in business, I too, feel guilty when I buy used, but the cost savings are the only way I can afford to buy what I like.-Though I always try to find a way to buy something from them, even though it isn't a big ticket item. I also try to give them as much free recommendations as I can. 
Bob

I think that 2c is a great speaker.  Personally, I wouldn't buy a pair  that was more than a year old.  I'd ask when they were produced.  Richard makes changes, like many top manufacturer's do and doesn't say anything about it.  It may just be changing a crossover point to warm up the mids, or changing components to a better one that they are able to buy in enough bulk to make it cost effective.  Lot's of little things they can do.  

I've sold and purchased gear used.  I know Bob bought my speakers, but he also came over to see and listen.  Speakers are funny as are transports and turntables.  IF you know the person you are buying from or can go see them before making the purchase, then that's great, but if you can't, I'd just be vary wary and make sure you read a person's feedback.  I've seen too many speakers, including demo's at some dealers (all lines of speakers) not in the shape they look like.  I worry about the socks as someone said above.  IF not careful, they can snag.  I also like to have a warrantee on a speaker.  IF  you can afford new, personally, I'd go that route if possible as warrantees are not transferable with Vandy's.  

Glad you love them.  Keep us posted on it all.  

The guys preceding this post are all on it.  If you buy used get a pair with the latest serial numbers you can from someone who presents with good feedback, unless of course they are in proximity to you and you can experience them first hand.

Again thank you guys for the sound advice! I do feel like it's important to buy new and get the factory warranty if you can afford it. Like I said previously, I've never bought second hand stereo equipment, but always lust after the savings. Especially because I sold speakers at one point and know their mark up. At this point, I really think that it's two pieces that need the upgrade, - the NAD, and the 1ce's and then I'll rest for a bit and listen happily. I believe the 2ce sigs may be my next ten years, unless there's a glaring contender (at $2500 or less) that is up to the full range competition that the 2ce sigs benchmark at that price. IMHO of course 😉Oh yeah, and just for a consensus, any opinions on online new speaker purchases? If you're out of state, you automatically save the tax, and usually without a stores overhead can get a bit of a discount (10-20%). Should I ask the local high-end dealer to match this? After reading Robert Harley, I'm hesitant to ask a dealer to match a reputable (music direct) online dealers prices, or for any discount at all, as I don't want to be offensive, or annoy them. But I'm not affluent, have to wait for my bonus to buy, and have a two year old little girl that takes most of my funds, so every penny counts here. Lol

Where do you live?  Who is the local Vandersteen dealer.