I had replaced some reaaaally weak (10 oz magnet, 20 watt per speaker) drivers in my 4x12 with Celestion G12H-80 speakers. The H-80s were the predecessor of the Classic Lead 80 and sound pretty similar. I also rewired the cab with heavy guage Monster cable instead of the thin original wiring. The cabinet now handles so much more power, can produce earth shaking lows, clear mids and breathtakingly beautiful bell-like clean tones.