Want seperates and have an integrated Mcintosh

I totally agree with Ghasley. The McIntosh MC452's (and MC601's) are amazing amps and I feel you will notice the difference right away in your setup. You could always add a preamp later or go direct to the amp if your source allows.

A new preamp will make a bigger difference.

I recently snagged a C50/MC452 on Audiogon, replacing a MAC6700 I really enjoyed, selling it to someone on Audiogon who loves his new McIntosh.
I moved my system to a room that was more than double the size and the extra power and the improvement in sound quality was immediately appreciated!
I know lots of audiophiles look down on McIntosh electronics, but to me it has a very "musical" sound, sounds great with a wide variety of speakers and most important, can be listened to for a long time, without being "tiring" to the listener.
I really enjoy my new acquisitions!