another + for app doas, especially the 992fet is a very nice opamp, he has plenty of 24 v opamp choices and his prices are more than decent.
another good thing about the 992 (which got my fav. actual ) is that building is much much more easy than the gar2520. i can do a 992 in less than 20 min, for the 2520 i took almost one hour to solder because it is very thight and crowded.
i think you can get a even better deal asking for 100 pieces.
the gar2520 of cause has the certain cream factor, while the 992 is more neutral and dynamic. the app2520 i only tested at 16 volts where it might be a tad less mid-aggressive than the gar version. the app2520 fet vesion has tighter bass than the before mentioned.
all of these opamps are equal right for making a hit record, the differences are real small between them( tested in the vp28 with its 3 transformers, which are contributing more to the sound than the opamps used )
greets
axel