Speed limiter

Do we have some tech/electronic freaks have here?? I've got a problem with my damn speed limiter- this thing is just shit!!! My ratio of the 5th gear is that high that i cannot hold topspeed (only 180- then the limiter limits me:( ) so I have to shift back into the 4th gear. It seems to me that the limiter is controlled buy speed, not by rpm at a specific gear. So what would happen if is simply remove the connection between ECU and speedo [not between ecu and tacho]??? Or does anyone have another idea how to remove the limit?? I havent found a garage which would do it for a reasonable price ( 150€ for 5 mins is too high in my eyes)!

Thx!