Typically more watts claim more headroom on transients and long loud passages.
No, not really. Our Class A 40wpc mono blocks outperform large mega watt amps. In general terms, when you upgrade the parts in the power supply with better parts like Nichicon, Audio Note and Amtrans capacitors, you usually get improvements in bass like deeper, faster, more defined and definition. You should also hear more openness and separation, more details. Highs and mids can have better separation and notes can seem to float. Sound stage can open up wider and deeper. For starters, replace the large power supply capacitors with Nichicon superthroughs. You can get them at Parts Connexion now called Audio Connexion. You can go up a size but just make sure they will fit in the chassis. They are not that expensive and you can see for yourself if you hear a difference. Form there if you like what you hear, send it out to a qualified tech to upgrade the other parts. We typically begin there and achieve excellent results.
Happy Listening.