I"m looking at buying an Traynor YCV50 Blue combo-tube amp. After reading the reviews on it, a couple mentioned changing the speaker to inhance tone. I had never even thought about changing speakers before, so i have some relatively simple questions.

What would the difference in 8 ohms to 16 ohms be? volume, tone, output?
The 'power capacity' is measured in watts but seems to have no relation to the wattage of the actual amplifier, how does the wattage of a speaker relate to the wattage of an amp?

Answers to any questions would be great. Thanks