Toshiba SD360

Hello Everyone,
I'm enjoying reading this forum so decided to ask a question. I recently bought a Panasonic 37PX60 and am very pleased(now that the replacement has been found to have quiet fans-the original tv droned like a station after closedown in the old days) My question is I am watching through a Toshiba SD 340 with component leads and find PQ very good but wonder if an SD 360 viewed through HDMI and allowing the tv to upscale(because reviews all say the Tosh's upscaler is poor) would be an improvement. Also I have seen people rave about improved sound via HDMI but does'nt that mean sound is played through the tv speakers which is rather defeating the object?