upgrading speaker crossovers

I have a pair of PSB Stratus Gold'is and I am thinking of upgrading the crossovers, I am going to try this before I think about buying new speakers., which are in the area of $10000. The crossover in a speaker consists of 1-2.5mf 440vac film and 1- 6mf 440vac film by RC. then I have 4 100mf 100vac electrolytics. Why are the elecrolytics there, is this because of cost? I would much rather put in polys in their place, which will cost me $30.00 each. So my question is are the elecrolytics there because of cost issues if so can I change them to ploys?

My equipment consists of conrad johnson PV14l tubed preamp and a conrad johnson MF2500 amp. Both are right now at cj to be upgraded, the preamp is also getting teflon caps. I also have a pair of Mirage M1;s that I have upgraded with SI tweeters and Woofers. Must have gotten the last ones from them because now they will not even talk to you about the speaker when you call.

Anyway any advise on upgrading the crossovers would be greatly appreciated.
Jchristilles ,
Glad you got much improved results with upgraded Mundorf Supreme caps . What were the original caps that got replaced?
Did you not replace all caps ?
I am told by a technician at a speaker mfg company that one should have all caps on the X-over of the same type and from the same company and not to mix different varieties ( not even from same cap mag company ) , e.g. not to mix Mundorf Supreme with Mundorf Silve-Oil .
The supremes need a lot of time for break in... The first time they sound hard and poor detailed. They change completely after a long time burn in.
I asked directly by manifacture in cologne, they need about 200 hours, to sound right. You can shorten this time with excellent results using the astonishing isotek cd enhancer. It works incredible good.
Timlub is correct about inductors.
However, replacing an iron core with an aircore is not a bad idea, especially in the woofer end of the circuit.
At the same time, it is a Very good idea to match the DC resistance of new to old.
My inductor design for my Maggies is within 5% of 'stock' while going from 16ga to 14ga. This buys power handling, reduces any chance of saturation to near zero while not messing with driver balance or crossover frequency.

The advantage is that aircore doesn't saturate like an iron core does. This will be of most use to those who like it loud....no....louder.
The two film caps I replaced were small in size and said RC on them. There were only two films per crossover, the rest are electrolytic caps and to change them over to film would be a hastle since the electrolytics are Radials and the fims are axial, very tight. Still breaking in the new caps and now that I have my new turntable I am spinning vinyl again!

Still thinking if I should change the electrolytics or not.
Still thinking if I should change the electrolytics or not.
I would. Unless you have a very large value, not enough space, or are on a strict budget, they don't belong in speaker crossovers.