I designed a tier 3 fighter for use by Grey aliens from Bestiary 5, whom I'm converting to Starfinder to use as the main villain for a one shot for my group. It's fast, tough, hard to hit, and powerful. It should be. Greys are an advanced civilization. I posted both the stat block and ship sheet. I've been hunting for inspirational artwork all day. Now I just have to design the PC ship.
http://crimsonovercoat-blog.tumblr.com/post/165421822943/grey-alien-saucerc raft