~400hp car on 15x9 6UL.

I'm in the market for a big brake kit (the car is currently running the 'sport' brakes). I really like the look of the new box mount 11.75 kit by Supermiata but I don't really want to buy a different set of wheels. I like the 6UL's.

Major bodywork also isn't something I want to do, so running huge spacers is probably out of the question.

What are the best brakes to use under these wheels?

 

Look up Tim Sherrington in the UK. He built an Alcon based 11" kit he runs inside of 15x9 6UL's. Recently ran a 7:42 on the Nürburgring with the set up. No idea if he would be willing to share tech, worth a try.
He's on the book of faces.

 

It's "just" brackets and hats away from using Alcon or AP Racing calipers and disks.
There seems to be some "internet" available from down under:
https://www.prospeedracing.com.au/al...a-mx5-nb-front

But if you can cope with Wilwood tapered wear (due to identical piston diameters) and reaming the holes in the spindles to Imperial dimension you can use the Mini 15" kit with Dynapro radials and 11.75" disks. Not the best but decent for the price.