In terms of your car running lumpy regardless of the rev limit, when the other guy fitted/had the cams fitted the timing would need to be adjusted as it clearly wouldn't be the same settings used as when standard cams are in place, if that is wrong then the car will certainly run lumpy. Also you need to have a look at what else is on the car because if the car is running high lift cams and letting more fuel in when the valves lift higher, it will need spark plugs that give a bigger bang and will also need a fuel pump/pressure valve capable of delivering the additional fuel and pressure. So if it hasn't got performance sparks (iridium minimum) a higher performance fuel pump and pressure valve then the car will probably not run vey well. Once you've sorted those things out consider getting a performance exhaust if you haven't already to get rid of the extra exhaust from the extra fuel being burnt and THEN go get your remap. Should be good after that.
If your car won't rev over 6500rpm the ECU is running the conservative map pre programmed by renault to protect the engine from impatient people revving the engine high which leads to engine damage when cold. When the oil is at the correct temp which is detected by the oil temp sensor that runs to the ECU, the ECU then switches to the normal map which has the increased rev limit as it is safe to do so when the oil has reached the correct temp. Hope this helps.