but what about the resistors in series on the tweeter/mid crossovers?There are two possibilities:
They are not part of the 6db crossover but the signal is going true them, confused!!??
1. The resistor is in series with cap that eventual leads to the mid/tweeter.
In this case, it is worth upgrading them to better spec resistors.
2. The resistor is in shunt to the mid/tweeter network then it is not in the critical path which means it is not critical so upgrading will not yield any meaningful improvement. But resistors are mostly less expensive so since you're already in there, might as well upgrading then as well.
I have not seen the xover network in person yet so I am not sure if the resistor is either #1 or #2.
Also, in my experience, caps make a lot more differences vs. inductors so upgrading the inductors may not yield a lot of improvement. That said, there is sonic difference between foil and wire type inductor. Having seen the xover in picture, the inductor coil in the bass xover is of wire wound coil inductor so it may be better to replace it with another wire wound type inductor. The original inductor looks like having a 16 AWG, so upgrading to something like 12AWG inductor may give you slightly more bass.
Also looking at some of the xover pictures, the wiring may deserve some upgrading as well. I guess it won't be much work to upgrade to something like Supra wire from Madisound.com.