Is It Worh Modding An Amp

No

Unless there is something deficient in the design, or parts have worn out, what is the point? I modded my Willsenton R8 integrated KT88 amp, upgrading and adding some parts (mainly resistors and audio path capacitors, and upgrading a choke) and I tube rolled it. I think it improved the sound a little and it improved the device reliability.

Just buy a new amp....go 300B and sell your old crap;..have fun. this is adventure..not a marriage. 

I modded a PL amp some years ago, film caps, Takman resistors, this along with really nice NOS tubes, especially some of the good Svetlana EL34 from back in the day were very nice improvement. Sold it at market value, still running fine to this day.  Some people will value modded equipment as equal to or higher than stock, others not. I've never let perceived valuations of others dictate my choices. The one thing I'd add is the simpler the circuit and less number of parts a component has the more a single parts change can affect sound quality. Small changes in my present 300B and 845 SET amps (especially the 300B) have made far more difference than those in push pull circuits.

If you mod it you are never going to get the money you invested in it back. Sell it and move on . It will always be a modded PL nothing more but a lot less.