Cary SLP98L upgrades--yea or nay?

I like the SL98.  It has been a while since I heard it, but, I like its rich and warm sound.  I have no idea what the upgrade will bring to the unit.  A local dealer who builds his own tube gear, mostly quite expensive units, truly HATES the sound of Mundorfs--he says they are dry and lean and harsh sounding--the kind of sound those who seek extra "detail" in the sound seem to like.  When people bring in gear to try to get him to take on their line, or when someone brings in something that has been "upgraded" he can tell they have Mundorfs in them just by hearing the item, without being informed of this fact.

For my taste, the SL98 does border on the excessively lush side, with some loss of dynamics and liveliness, but, I like the sound overall and would be a bit cautious about a modification that might change its character drastically.  If you go that route, make sure that you can undo the modification if it is not to your liking (have them give you back the replaced parts).

"I like the sound overall and would be a bit cautious about a modification that might change its character drastically."

^^^ That's exactly the context for my post, and I appreciate your clear articulation of it. Dry, lean, and harsh ... would be a big step backward for me. I've mostly read positive things about Mundorfs, but I've also heard some negative comments. Thank you for your response!

I had a Cary SLP98 with the F1 upgrade. Without a doubt it was my best preamp.

Thanks, Russ. I've read a lot about the F1. I think it's close to what Cary offers but with different caps. 

I wonder if I could find a tech who could reproduce the F1 upgrade....

@northman yes, your list +Grayhill switch selector.

These upgrades and different tubes can yield good results in different ways. Having tried rare vintage NOS quads, new re-issues, and some of the new boutique 6SN7s, the sound will change, and more so with good caps installed in your SLP-98L.