Can't go wrong with Defi and Bride (but I'm biased lol), it all depends on how much you want to spend
I went the 60mm gauges, it's a bit of a pain to have them sitting flush inside the housing. I had to make up a plate to sit on the inside for the cups to sit on
As for the seats, I was in the same thinking as you. I wanted to go the GTR seats but you're looking at atleast 2k for a pair in good condition.
I payed ~$500 more and I got a brand new pair of Bride Euro 2 + rails