Curl or Pass

I would seriously look at Tom Evens range of phono stages, many hold him up as the Messiah of phono stages. Has models that have big gain so you only need a passive pre to go with them, and have switchable adjustable cartridge loading impedances.
http://www.audiodesign.co.uk/

Cheers George

PS: here is the US agent for them

https://www.soundbysinger.com/high-end-audio/phono-stages-and-catridges

Both phono pre amps you mentioned are built by incredible talents you would probably need to hear them in your system to decide between them. Pass and Parasound are responsive to calls so you could contact them with questions. I haven't heard either but going blind would lean towards the Pass as it is American made and hardly ever shows on the used market which must tell you something.
Good luck happy listening.

I’ve had both.   I’d give the edge to the XP-15 (although they’re close enough that sometimes its simply about what is available when you want to buy)

I have the XP-15 and it is fantastic.  I also have a Manley Chinook to compare it to.  The XP-15 is a little more detailed and very neutral and has a ton of loading / gain options.  No experience with the Parasound unit.