The 25 tempest should increase your RPMs even more. My suggestion would be to have one or both of your props reworked to reduce RPMs. A good prop guy could take off 2-300rpms and you should still have your hole shot/mid-range. A good worked prop will be much more efficient with prop slip as well. I have only worked with John Janaky at DAH and the results were exceptional for the costs. Boger props is supposed to be top rate as well, but more expensive also. You will be happier with a custom worked prop. Keep that motor around 6000rpms top end and you will be happy with the results!