Hi,
That's an interesting mod that you're gonna try. Do let me know what the outcome is. I am sure the sound will improve, just to what degree.
I wasn't gonna mod the Xover, cos it's just a simple first order design anyway, with a capacitor, coil/inductor and a resistor to account for the higher sensitivity of the tweeter. What I did do was to look round Vifa's site and saw that the original swift drivers are really their cheapest range, hence why I thought of getting their more expensive drivers as "drop in" replacements, since their sensitivities and load/ohm rating's the same. Their Thiel-Small parameters are a little bit different but only for the mid/bass driver, which I am sure will not matter since the swifts use a transmission line like loading system.
Did you get the Django from DIY Hi FI Supply? I got my Seiden and DACT stepped attenuator from him. I was thinking of a Django but then I realised it used the same Seiden selector switch and it was cheaper and more customisable if I DIY'ed. I have to say, in the system that I am using the passive pre-amp in, it was one of my best decisions! The improvement in sound quality is tremendous, no lack of dynamics either. I originally got the idea when I tried my CD player direct into the power amp, bypassing the active pre-amp I was using at the time. I was able to do this cos the CD player had a variable analogue output control, but since the lowest setting on that was still way too loud, I had to look for an alternative which didn't take too much away from the signal. Hence the passive pre-amp, which basically is just one long interconnect with a resistor in the signal path to alter the gain and give volume control. Since I used pure silver wires throughout, I reckoned that the signal loss would have been less than what it would be in an active pre-amp.
I had also compared the DACT/Seiden passive pre-amp to other active pre-amps, including the Bryston BP-20/BP-25 that my friend has. Needless to say, since it was feeding a 4BST power amp, my passive pre sounded so much mre transparent, detailed and gave a more 3-D soundstage than his BP-20/BP-25! So much so that he was tempted to DIY his own passive pre-amp!