I always thought amplification is most important.Any mistake you make gets amplified. It's just the speakers are so much harder to get right.
The amplifiers amplify any mistake, but I think that at the current state of the art, the amplifiers add the least distortion in the chain. Some amplification add euphonic distortion, and I don't like that, but I know some do.
According to Touraj: of the turntable/tonearm/cartridge triumvirate, he thought that the weak link was the tonearm, and hence his work on the tonearm.
One element that I did not mention because so many on this forum do not believe in cables making a difference, is that all the cables in the system was also designed by Touraj. He thought that the weakest link in many systems was the cables, and hence that was his first product.