PASS LABS XO.2 Preamplifier 3 Chassis or Pass Labs XP-10

I am looking for a used Pre from Pass Labs. The question is for those with experience in both or with one of the above mentioned. I don't want to spend $4500 for a XP-20 or more. I want to stay in budget. I can get a XO.2, the 3 chassis classic reference or a newer XP-10; and don't presume newer is better. I'm okay with older if it does what I want.  My future amp is a First Watt F7 or Pass XA. I'm looking for feedback on the Pre's. 
Toddcowless; you remind me of a good point I read in some reviews if I remember correctly, the XP-10 has bass plus, but XP-20 has bass in a controlled, subtle and appealing way. I've had some great CJ pre's like GAT version2, ET-7, and have an ET-5 and Premier 16LS2, and Premier 17LS. The most quiet were GAT -2 and ET7 as well my ET5. I can not say the Premier 16/17's are at all noisy, but they are warm and inviting with detail still. The XA25 arrives next Friday and I have a weeks worth of burn in till listening. Thanks for the XP-20 thoughts. I'm thinking.... 



i know this is years old… I own a premier 16. I just heard a INT150 I bought for a friend in my rig and have never been so musically connected. Like can’t stop listening to music   

what were your experiences moving over?