JBL 4311WX-A recomendations for mixing/studio use?

What are your recommendations for a power amp for these speakers? Been using them with a QSC RMX 850 amp, but I just bought a completely gone through Yamaha P2200. Hoping it's a bit better match.

Has anyone done the Jantzen L100/4311 crossover upgrade? I am somewhat reluctant A) because I don't want to be w/o my 4311 for an extended period of time, and B) I'm somewhat afraid of tweaking/losing the "classic" 4311 sound that so many of my favorite albums of the late 60's and 70's were mixed on, and that the JBL's were made to represent. However... I'm told that the crossover really just lets you ring out every last drop of usability of the 4311's complement of drivers, since they aren't really being used to there full potential with the stock x-over.

Any input would be killer. Thanks all!