WHAT'S THE DEAL WITH WATTS?

A few notes...

First, efficiency of 93 db is a moderate efficiency. Its likely though that these speakers are really rated by sensitivity instead of efficiency, if so then the actual efficiency if the speaker is 4 ohms will be 90 db. I just noticed the tis49 stated exactly the same thing above.

In the average size room 200 watts will be nice to avoid clipping when 'rocking out' but it will be right on the edge. I had speakers of 89 db 1 watt/1 meter and I found 200 watts to be barely enough power if I was pushing things.

Let's talk about 'current' for a moment- there seems to be the usual confusion about what that means on this thread (based on the use of the phrase 'high current') so let's go through the math:

Assuming 300 watts from the amp and a 4 ohm load, the power formula tells us that the current really isn't all that high:

Power = Current squared x load impedance

300 = Current squared x 4, solving for current we get 8.66 amps.

The thing to note here is that it makes no difference the technology of the amplifier, if it can make 300 watts into 4 ohms then the current will be 8.66 amps. If 8.66 amps does not seem like a lot to you, then we have the germ of a conversation you might want to have.

WATT DID YOU SAY??

Its nice to use an amp with more than enough power to drive a given speaker past its limits. Of course you don’t want to push so far as to risk damaging your speakers. I like having more dynamic range on reserve for those bursts of sound that call for it. Not only with higher frequencies, bass sounds richer and fuller. The only time I pay attention to wattage rating and become intrigued enough to investigate more is when the amplifier is high current and watts double or close to double when impedance is split in half. Then I will check output capacitor and transformer size and VA rating of the power supply as a whole. Wattage ratings are not always very telling of an amplifiers performance. When I had a Sim Audio W 4070 that was rated at 70 x2 at 8 ohms it got me wondering why it sounded so much heftier than some other amps with double the wattage rating. Then it had me seeking answers. Looking at its specs and comparing them with other amplifiers. Search for meanings and get a feel what to look out for. The sim is a great "little" amplifier. Not many amplifiers will match its spec to size ratio. I would consider it above average in terms of power ratings and specs. 

P/S Transformer 750 VA
P/S Capacitance 100,000µF
Class Of Operation A/AB
Single Ended inputs (normal & phase-inverted) 2 pairs
Balanced inputs 1 pair
Input Device Type J-FET
Input Impedance 47,500 Ω
Input Sensitivity 750mV
Output Device Type Bipolars - 4 / ch.
Output Power @ 8 Ω 70 W/ch.
Output Power @ 4 Ω 140 W/ch.
Output Power - Bridged Mono 300 W
Bandwidth (+0/-3.0dB) 10Hz - 75kHz
Output Impedance 0.025 Ω
Damping Factor (static) 320
Gain 27dB
Signal-to-noise Ratio > 100dB
Maximum Output Voltage 26 V
Slew Rate 15V/µs
Maximum Peak Current 20 A
Crosstalk @ 1kHz -100dB
IMD unmeasurable
THD (20Hz - 20kHz) < 0.1 %
AC Power Requirements 120V/60Hz

Power, watts or amperage isn't going to tell how an amplifier will sound compared to another. I can only provide you my real life experience with Jeff Rowland products. I had a Jeff Rowland Continuum S2 Integrated Amp. The S2 is rated at 400 watts @ 8 ohms / 800 watts @ 4 ohms. I traded the S2 to purchase the 625 S2 amp. The 625 S2 is rated at 325 watts @ 8 ohms / 600 watts @ 4 ohms. Everything about the 625 S2 is better...the soundstage, bass, mids, highs, tonality. Unfortunately, specification don't always give an indication of how an amplifier is going to sound. The Continuum S2 is Class D and the 625 S2 is Class AB. My point is there are other factors that determine an amps sound that has absolutely nothing to do with its power rating. In my opinion, it's better to spend extra money to get a better sounding amplifier; not necessarily a more power amp!   

The again, not everyone hears the same...an upgrade to one could be nails on a chalk board for another!