Go for the Porsche brakes instead since you're going bigger anyways its nearly the same pricenice.
im doing chassis first. gathered most stuff allready, all polybushes. audi tt subframe and steering rack. only need the hubs.
coilovers, brembo cupra R brakes. but dont know about the arb's. and yeah the haldex controller is also on list for when i have more power.
I will definitely look into going bigger. The vband outlet on the turbo is 2.5" but I'm sure it can be adapted straight to 3.5. Your the 2nd person to say that 3" will be too restrictive.