I suppose it depends on whether or not you are happy with the sound and/or what kind of vinyl playback gear you have. Personally, if all of the components on the board are within spec, I don't think the phono stage is all that bad. It is similar to that in the PAS so I don't think you're going to notice a huge difference.
This gentleman looks like he may have an interesting drop-in replacement/upgrade phono stage availble for the SCA-35 later this year:
http://www.audioregenesis.com/products/ ... index.html
Also, Joe Curcio has some easy upgrades for the PAS phono stage on his forum:
http://db.audioasylum.com/cgi/m.mpl?for ... =&session=
These may be applicable to the SCA-35 as well although I haven't given them a good enough look to be sure about this...I just offer it as more information.
Joe
BTW - I like your avatar. Yellow_Light_Colorz_PDT_12