Thanks Glynn, I received the capacitors and installed them early this week. I should clarify for the rest of the group that we believe these capacitors are actually metalized polypropylene; not paper in oil as they were advertized on eBay.
These film capacitors look nice enough and performed well. I was a little concerned about desoldering the original caps, as I'd hate to chance lifting a pad or trace off the pc board, but the operation went well. I listened for changes this past week. I think if there is a difference, it is too subtle for me to clearly identify. Maybe drums kits sound a little punchier and complex passages are somewhat more articulated. Of course, that could either just be in my head, or simply due to cleaned connections from reconnecting the cables. I'll leave them in because they're performing fine, but I don't think I'd recommend the update to others for a few reasons: the old caps (also metalized film) were sturdier, the part swap requires rework on a printed circuit board, and the circuit location is unlikely to change the sound much. I'm looking forward to Grainger's feedback.
The final point I'd like to make about the update, is that I had a good time anticipating it, performing the update and listening for changes. I had been letting a little dust settle on the rig so it was nice to be reminded to enjoy the system. This is a great hobby! Thanks again to Gylnn for his gracious offer (free stuff!) and subsequent off board communication. I hope he's enjoying his remodeled room right now.