Agree with Lostbears. I used to own the SP-17 and switched it out for the Ref3. As I'm sure you know, the SP-17 is not an LS-17, but minus the phono stage. They are different units. ARC refers to the LS-17 as a "Baby Ref 3." If you go the LS-17 route, you may want to try to swing the few extra bucks it will cost to get into a used PH-7 Phono Pre. The PH-7 is much improved over the PH-5. I also own the PH-7 and love it!
Not to mess with your head too much, but it may be worth a call to ARC to speak with Calvin. He's a real nice guy and may be able to advise you how to get the most bang for your buck. For example, your 150.2 amp is a Class T SS amp that ARC discontinued in 2006. Cal may suggest (??) that part of your upgrade include changing out the amp and going a little cheaper on the pre. Just a suggestion. Good luck.
Not to mess with your head too much, but it may be worth a call to ARC to speak with Calvin. He's a real nice guy and may be able to advise you how to get the most bang for your buck. For example, your 150.2 amp is a Class T SS amp that ARC discontinued in 2006. Cal may suggest (??) that part of your upgrade include changing out the amp and going a little cheaper on the pre. Just a suggestion. Good luck.