depends on how its ported, but the pipes(length) will dictate the rpm more then the exhaust port will to a certain degree, it just depends if its raised which will require more rpm or widened which will keep the same rpm. You have a little bit of wiggle room on raising it a bit and gaining hp at the same peak rpm where it was stock.
The only way to know is to dyno the engine set up if whoever ported it didnt give you the information on where the peak hp will be. On a srx with stock pipes you are not going to be able to run it past 8650-8700rpm with the stock cdi or it will for sure lose peak hp.