From what I can tell, people have gotten amazing results from wearing "partial" systems. If the colour match is right, when you cut it, it will blend right into your hair system and will look amazing.

Ask BA about this, he's done some great jobs on people who have gone to him to get this done.

That said, a topper might be even easier. I'm not sure which part of your head you want to cover, but you could fill out your hairline nicely and make it lower down.