@DEVON
My first FJR was dealt with that way and it ran well until I sold it at 47000km.
I re-restricted it for the sale, I didn't want to sell a non legal bike.
The problem with doing that is that you must be sure that the metal filings are completely washed away before re-installing the pipes.
My present bike I bought new (uk style) pipes
The mod to the ECU is negligable compared to the restrictors, the difference is around 1 or 2 HP, I believe the power curve is modified slightly as well.
@ShanFR
If you were closer Shan I could lend you my original pipes the time it takes to register your bike, mind you the cost new is around 45 to 50 euros if I remember rightly