Changing of electrolytics can increase the realiability and improve the sound and preformance of the amplifier but please be advised that this is an activity that can be very dangerous so please ensure that a suitably qualified or experienced valve amp engineer / tech does this.
The custom 15 controlled power amplifier on the panel is different to other of these amps that i have seen as a Watkins Scout and as an early squarebox Wem Dominator. Personally I think that these amps sound great.