Its really a matter of bringing a knife to a gun fight. The manufacturers are being pressured more and more to make their vehicles compliant and being held responsible if they aren't. They have the money and the engineers to protect their business. Before long things like ECUs will be tamper proof. As noted earlier, they will just stop functioning if they detect anything unusual. Of course they won't shut down while they're running, but just like now when they set codes, they will test themselves a few times, display an error and if left uncorrected, at some point they just won't start. ECUs will have to match VIN numbers, coded by dealers only of course. It won't be long before the days of modifying current production vehicles becomes virtually impossible. My two year old car doesn't even have a dipstick. Pretty soon they won't have a hood release. You get the hood open, you void the warranty.
Sure you'll be able to cobble together a bike from parts. But how long will the powers that be allow things like that to be registered. The handwriting is on the wall. We're likely getting near the pinnacle of development in terms of high performance, internal combustion, bikes and cars. Enjoy it while it lasts.