PRICE IS USD
 
A Royal Enfield Brembo brake upgrade, to allow fitment of a 4 piston Brembo calliper.
  
Includes the four necessary machined parts and hardware to fit the 4 piston calliper and 330mm rotor only.  In addition you will need to buy a: 
Brembo 330mm rotor 
Brembo P4 calliper with a 65mm axial mount
Brembo RCS-15 radial master cylinder with reservoir, input fitting, and switch
 
The combination of these parts, results in a front brake system with not only greater calliper piston area than stock, but also additional brake torque provided by the 10mm larger diameter rotor. In addition to far greater brake torque, the adjustable ratio, radial master cylinder gives superior "feel" and the ability to modulate braking up to the point of the ABS kicking in. 
A huge step up in brake performance when compared to the stock budget brake.

There are 2 Brembo P4 callipers that will fit - The P4-34 with 4 x 34mm pistons for a 20.2% increase in piston area, 4 pads for greater initial bite, and a more rigid triple bridge design; or the P4-30/34 with (2 x 30) + (2 x 34mm) pistons, for a 6.9% increase in piston area.

The rotor is a common Brembo or aftermarket part.

A 15mm bore master cylinder is needed due to the larger piston area, and the recommended model is the Brembo RCS-15.  This is a radial design, with adjustable internal ratio to tune the feel to the Riders preference.  

Not a bolt on installation, and one must sand or file 3mm off the ABS sensor boss.  Not difficult as the amount of material removed is not overly critical, and one may have to shim for final sensor to ABS ring clearance, just like the factory had to........
The stock brake line can be re-bent to fit.  
ABS functionality remains as per stock

The stock M10 (left hand thread) mirror will not fit the Brembo master cylinder mount clamp.  The Brembo clamp mirror mount is M8/ RH, therefore should you want to keep the stock mirrors, you will need to buy a generic clamp.