Michaeljbrown...
I can heartily recommend Pass Labs X150.5 or up. I've seen a few in your price range and to my ears were the best amps for my CS3.5's.
The X150.5 is 150 watts X 2 into 8ohms, 300 into 4ohms. I had an ARC LSB2 for the preamp.
Also, I can recommend looking into a Pass via Reno Hifi here. I have no affiliation or mercenary connection to Reno but my two quick transactions with Mark were exemplary. I purchased a First Watt M2 from him and almost immediately stepped up to the 150.5. Full credit for the M2 towards the 150.5. Pass ain't cheap at any level so knowing you're dealing with a class act is reassuring.
Have fun in your quest. Thiels reveal!