You can remain with 14" but switch to AP-Racing or Lukas like stuff. So as the rear brakes, it's quite a common tuning among car tuners in here Russia.. All you need is good metal turner to make an adapter
The 14" brakes as they are called on Russian tuning pages and in tuning shops are the ones that have 259 mm diameter. And that's exactly what I want to have on the front. Just need to find the right calipers. With this diameter the brand of the discs and pads won't be that important, I think.
You can of course have good braking with 239 not vented that I have now but you'd have to by top quality discs and pads. I had been once offered such discs, from Tar-Ox that - as I was said - were doing very well in some rallycross Samara. But the price for a set of those was about 350 euros. So it seems more reasonable to spend the money once on swapping into 259 mm discs and later on have good braking even when using discs and pads that don't cost a fortune.
When it comes to the rear axle: I've found everything I needed on http://www.team-rs.ru
. Will just have to find sb. who will do the adapters but that's not a problem. This change will of course be followed by the installation of hydraulic hand brake and, above all, a proportioning valve to regulate the braking power between rear and front axles.