Want seperates and have an integrated Mcintosh

have a MA6600 and can't afford both a MC452 and a C50/2500. Should I buy a pre and use the integrated amp side or buy a mc 452 and use the integrated pre ?
If you can completely bypass the preamp in your integrated, I would go with a new preamp first. The only exception would be if your current amp doesn't have enough power to drive your speakers well.
Sounds like you have the cash to swing one or the other: the amp or the pre, is that correct? If so, I would recommend you buy the amp, search for a preowned c2300 and sell your integrated to fund that purchase. Good luck.
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!