G'day all, noticed yesterday that my speed limiter hits before rev limiter in 4th gear, (around 4600).

I've got a dyno run coming up soon, can i run it in 3rd? or is there a way of getting rid/around the speed limiter?

I could use my 3.9 ecu which has no limiters, buit will the performance drop as compared to my ED 4L ECU?

Cheers.