It is all about how handy you are......
They even put Chevy V8 blocks into a Mini Cooper so if you are handy with a dril and dremel it is possile.....
You want much CC into that car, the Picco P2 Maxx is the way to go with a direct fit, it comes in a .21 and even a .26 version. Let me remind you these engines are nor RPM monsters so more speed is impossible unless you can change the gearing a lot so you can convert the tons of torque into speed.
Speed is only fiction but a 130+km/h MRS4 is for real.