If you take all the steps that are suggested, there is no way you will have overheating problems. I replaced open grill, back to standard. The holes behind the numberplate, do not affect the structure, just remove plate, when on track.Bonnet vents are not needed, providing the fan is the right way round!!.( Thats another subject.) I have fitted an over ride switch for the fan, but never used, temp. on track remain normal.(ISH!.) With the work you have done, I am sure all will be fine. Take care at the ring, and enjoy. I will be at Spa/Ring, mid July.