The only way you are going to be able to make that kind of power is if you rev the motor out to 8k+ RPM. You will not be able to do that with a stroker kit.
The 40R is still somewhat unproven. The 4088 is a turd turbo that is not worth anything for high boost. The 4094 looks great on paper, but I've heard it spools like a 42R with way less power....might was well get the 42R then. The 35R will make 600whp if the appropriate accompanying mods are done.