Need Help Putting Together My System

My present hook is HCA 2 Amp; BAT SK31 Pre-Amp; Nagamichi DR10 Tape Deck; Simaudio Equinox CD Player. Cables are MIT Shotgun S2 Speaker; Cardas Neutral Ref XLR and RCAs - XLR runs from AMP to Pre-Amp; RCA from CD player to PreAmp; etc. I am thinking of changing my MIT to Cardas Cross Speaker cables and my Amp from HCA2 to Macintosh MC252. Any insightful advise or comment would be appreciated.
Suggest you change only ONE thing at a time and then hear the difference. Even better if you can audition an item first before having to purchase.
Good Luck!
GOOD idea only one change at a time, too many and its hard to tell what is doing what.