Thiel 2.4 or 3.6, which to get?

Hi all,
I have Thiel 3.5s and really like their sound, but am on the horns of a dilemma. I have been thinking that my next step up would be to find a pair of nice used Thiel 3.6s, but have run across a pair of dealer demo 2.4s which have never been sold and which I can buy for $2300.00. The dealer who has them in his warehouse is very open to letting me audition them at my home, but is a two hour drive (one way) away from me. The idea of having new speakers with the full warranty appeals, but driving four hours to get them and possibly four hours to return them if they are not a substantial improvement over my 3.5s, plus the roughly $1000.00 additional cost over some nice used 3.6s, (if and when I find some) gives me pause.
So, althoughI have gotten some helpful input from a previous post regarding this issue I am hoping for more or new input from Thiel knowledgable 'Goners because I actually need to make a decision in the next few days.
If the feedback I get here is that the 2.4s are a substantial step up from the 3.5s and at least a noticable step up from the 3.6s I will pull the trigger, take a day off work, do the driving and pick them up for an audition.
What I like best about the 3.5s is their transparency, detail, soundstaging and bass. More of these characteristics is what I am hoping to get in any upgrade I make. All inputs from folks who have actually owned or heard these models will be greatly appreciated.
I predict that the 3.6s will be more extended in the bass if you are used to the 3.5s, compared to the 2.4s. This also depends on your amplification which I assume is suffucuent if you have been driving the 3.5s satisfactorily. I have the 2.4s and their bass is adequate but not nearly as extended as my CS6s. The 2.4s do have a wonderful huge soundstage and the mids and highs are sweet. Plus, not knowing how large a room you need to fill could also play into the decision.
Neither the 2.4's or the 3.6's can match the depth of bass or the overall coherence of the 3.5's, and even with the demands of the 3.5's eq, the 3.5's are much easier for an amplifier to drive.
On the other hand the the 2.4's and the 3.6's are more refined from the mid-range on up, and more extended in dynamic range. The 2.4's have a tough phase angle and low impedance, the 3.6's have an easier phase angle but an even lower impedance. Both need an amp with real muscle.
IMHO, the 3.5's just might be the best used speaker value available today, just so long as you realize that they probably need an amp that costs more than the (used) price of the speakers, to appreciate all that the Thiel 3.5's are capable of. Still, it would cost many times the combined cost of used Thiel 3.5's and appropriate amplification to match, never mind do better.
Thank you both for the input. I have decided to pass on getting the 2.4s despite their bargain price.
Unsound, if you are willing, I would like to ask you some more Thiel related questions. The contact user function on Audiogon is not going to be up and running 'till the end of the month, so if you are open to giving me some guidance please send me an e mail at:
Although the 3.6's can go a little deeper than the 2.4's, the 2.4's will be more lifelike and better integrated. It's a truly astonishing speaker! For that price, I would buy them and if you decide down the road that you Woukd like to upgrade to 3.7's, then you can easily sell them for a profit.

Chose between 3.6's and 2.4's last year and I now have a pair of 2.4's that I simply adore