Just seeing what the difference is between running a set of 2ohm component speakers vs 4ohm. The amp is good for 2 or 4 ohm.
The amp plays 50x2 @ 4ohm or 90x2 @ 2ohm.
Is it better to buy a set of 2ohm or 4ohm components speakers ?

 

The impedance should not noticeably affect the sound quality as long as the amp is ok with it. You will get more power with the 2 ohm set but the amp will run hotter. In this case it is even more important to make sure your amp is installed with adequate air cooling. It may shorten the lifespan of your amp a bit too but it's not something I'd worry about.