2000 Mustang Gt Swap??

I personally love the Coyote motors but, with that being said go ahead and take your budget for the build and double that because you're going to need it. Back to topic, either of the motors you selected have potential of being a killer street machine so which ever you think you'd prefer to spend time and money on and which one you think you would have a better time installing in the car so look at things like motor mounts k members etc..

If you want to make it as fast as a terminator Cobra just swap in a 4 valve mod motor and slap a kenne bell on it and there you go you're as fast as a terminator

I think swapping a 4 valve would be easier but I don't know for sure. Seems like the tech of the time would speak better to the car of the same era.

That being said, then coyotes are freaking impressive. In the end, I think you will spend more swapping the coyote.

You could look into a custom 2 valve build. Trick flow heads on a built bottom end, healthy cams and a kenne bell or a custom intake with a centrifugal blower, that's a mean stack of horsepower. Shoot for about 600 horse at the wheels with a engine that slips right in without cutting up your harness. You'll have to upgrade the fuel system and MAF. Beat down on porshes with that kinda power.

+1 to what @Mattstang04 said either a 4Valve or an extreme 2Valve build can make all the power you want