Apex'i RSM is what your thinking of Fin. They are not too hard to install if you are electrically minded. Although you can get harnesses to save you cutting the wires at all if you want.
the speed converters cost around £30 IIRC. Spea to Dunx or other car importers on here. theyre probly keep a stock of them. They convert your speeko to MPH, so theyre just pushing the limiter up to 190mph. lol