Dcathro.......Black gates are a matter of taste, I have found them overated they take months to breakin. As an alternative the Elna silmics I &II's are very good strasight from the off. Don't forget to tweak the psu ....if its running the standard 1n400x rectifer diodes swap for 11DQ10's or higher. Bypass the res caps with decending values of 10% ie if you have 10000uf bypass with 100uf 10 uf 1uf. If your chopping the case about to make a top loader, the integrity of the case plays a part in the overal sound. You may need to brace the rest of the case.   If your swapping opamps etc use good solid copper pin  sockets, even dropping back the same opamp has often given a better performance [better contacts less solder who knows why ?]. Don't scimp on the sockets either !