Best Integrated amp for under 4k

I'm currently using a Krell S-550i Integrated Amp. to power a pair of Wilson Audio Sasha 2 Spkrs. in a large room and it sounds very good, with excellent dynamics, micro-detail, imaging, and deep bass, plus plenty of good clean power.

I recently ran a $7,500- Pass Labs INT-150 against it and the Krell performed far better across-the-board, with what seemed like twice the power - it was no contest.

The Krell S-550i reminds me more of my previous Pass Labs X1 and X250.5 combo. than the INT-150 did, it's that good and could be had for well-under your budget.

Given that this thread has been resurrected, I'll offer my two cents. 

Musical Fidelity M6si

TY- jmvs

the only caveat of the 330i and 550i, is that, both were made in china.

The Krell Vanguard is the best sounding integrated that they've ever made.  It does everything well.  Speed, detail, huge soundstage, bass depth and snap.  It takes a lot of money to beat it.  It retails for 4500, slightly over the original poster's price, but can probably be found for ~4000 without too much trouble.  It's an awesome sounding unit.