You'll probably find the RS pipes will make the motor peaky. The loss of midrange will not really be compensated for by the top end improvement and the pipes are tuned to peak over 12,000rpm, whereas the NSR exhaust port isn't, so there will be a mismatch.

One thing you could try is to make longer exhaust stubs at the exhaust port exit. This lengthens the pipe, so brings it's tuned length closer to the range you need for a stock engine.

And yes, they are loud.