Fostex 206 EN(?) upgrade


I'm have an upgrade itch to scratch. 

I own a set of BLHs based on the Kirishima on  The Spawn Family of Double Horns (frugal-horn.com) . I was wonder if there was a drop-in driver available that I try that would be an upgrade over the current Fostex 206 EN (I believe them to be ENs) I currently have. 

I'm very happy with the speakers although they do sometimes exhibit a "shout" at high frequencies which are most noticeable with female vocals, strings and piano. I never had this with vinyl but I have switched to streaming a while ago  and suspect the digital to be a smidgen brighter and getting the better of the drivers. 

thanks
pauly
Contact Fostex. I was just looking for replacement 7 inch drivers for my Moth Audio Cicadas so I was looking at Fostex and Lowthers. Fostex will know their product line better than anybody. Ask them and you’ll get the right answer but it looks like they have better drivers that might be the same cutout size. 
fostex fe206 are some of the worst speakers ive had
ref 3a decapo would be a easy upgrade
Got a pair of fe208e Sigma's as per Johnk's recommendation. Very very nice.

The improvement is very subtle, but the treble is more polite and delicate now. I was worried that the tops would be rolled off, but they seem at least as extended as with the 206EN's.