Re: can the speakers be replaced for a bigger size in the line 6 spider 2 210 amp??
The last time I looked at one I recall there being enough room for a pair of 12s, I think. Just make sure the ohms match and your only limitations are physical dimension and of course your ears. I wouldnt cut a new hole till your absolutely sure your gonna keep em and then only if you have enough room to cut without weakening the baffle, which you probably wont, you can flush mount them from the back and youll be fine with the 10"+ hole that is there.
Be careful what speakers you choose, sometimes modeling amps and guitar speakers dont work well together. Youll get a funky sound. Modelers are made to work in a more flat range whereas guitar amps are more humped in the mids and the speakers will overcompensate for that. Im saying dont go drop a couple hundred on a new pair of celestions before you try some with it first. Peace