7xl specs?

Im new to this, im trying to get it

So (just looking at the xl motors) on the same number of cells a 7xl has more torque than a 8xl but the 8xl will have more speed than the 7xl. so the higher the number( 7, 8, 9 etc) the higher the top speed, but the lower the number the higher the torque.

Does that sound right?

but serum said

"The torque is always the same (with a motor from the same range (xl serie, L serie, S serie)"

So the torque of a 7xl is the same as a 8xl, 9xl etc. and the torque of a 7l is the same as a 8l 9l etc?