What effect will removing a whizzer cone have?

I am considering building a speaker based around one of several 8" "wide range", paper cone drivers which use an additional whizzer cone to extend the frequency range (Lowther, AER, etc.). However, I have never been really satisfied by whizzer cone highs in other speakers, and the interaction of the whizzer cone and the main cone always does seem to produce some upper mid and treble problems that are irritating. So I am considering adding a tweeter to the mix, not just to supplement the highs above 10kHz or so, but to replace what the whizzer cone altogether.

The obvious question is: other that cutting off the high frequencies generated by the whizzer cone, what effect, if any, will the removal of the whizzer cone have on the performance of the main driver? Will it "screw-up" the sound of the driver altogether? Might it improve the reproduction of the frequencies that the driver still produces? Since the driver was designed to have a whizzer cone, will removing the whizzer cone badly skew the frequency range of the driver (other than cutting off the highs)?

I realize that this is an impossible question to answer fully and accurately without being in reference to a specific driver, but any general notions or ideas of what would happen would be greatly appreciated. Hopefully, some knowledgeable A'Goners out there have done this type of experimentation before and have formed at least a rough idea about what is likely to happen (such as, where will he driver sans whizzer start to roll off?).

If it really isn't possible to answer without knowing the driver, I do have a pair of used Lowther DX4s, and I can get my hands on a pair of used AER MD 2Bs.

Great thanks in advance to anyone who has any knowledge they can share on this matter, or knows where I can find it.