Sorry, I check the forums every few months nowadays, but this may be of interest to some.
I've had 2.4s for years. When the SE came out, I called Thiel and asked them which brand/model 'boutique capacitors' they used where in the crossover. They change out the two capacitors that are in series with the coax driver (27 & 13 uF), from standard issue Axons to Clarity Cap SA. So I one-upped those and got matched-pairs of the next Clarity Cap model up, the ESA, and bypassed them with Vishay MKP 1837 as per the 'humblehomemadehifi' site. Total parts cost from PartsConnexion was ~$130, and accessing the crossover is easy as was soldering them in.
Obviously I couldn't A/B them anymore, esp as it took probably 200hrs for these giant caps to settle in and sound their best. But I can say that the speakers have never sounded better, and it does allow the coax to be all it can be, with far less veiling than the stock caps -- if audio memory serves. I can't swear to it, as these are the only caps inline with a driver, and they're matched to <1%, imaging improves too. Not a bad mod for a couple hours and $130.
Having said that, unless you're a Thiel junkie, I'd certainly buy used 2.4s (with outriggers if you want) and then throw in even better caps than the SE uses for a whole lot less money than getting one of the 150pairs of SE. And if you somehow think the 2.7 is a great deal at $10K, I can assure you it's a far better coax than the 2.3/2.4 units.
TMI