Hello from sunny (actually, rainy at the moment) Miami! I'm glad you were able to become a proud Mustang owner... welcome to the site! You'll find plenty of great info and people here.
As far as your Mustang goes, it's a great start. Just wanted to point out that there is absolutely nothing wrong with having the six-banger. On the contrary, they make great low end torque and are tough as nails. Plus they give you an amazing amount of engine bay space, making them a perfect candidate for a beast turbo setup. I saw a guy at a local show a few months ago bring a mid 60s Falcon set up for drag racing. That thing sounded like no car I'd ever heard and was practically the star of the show that night. When he popped the hood, there it was... a fully built six cylinder with a massive turbo. Amazing. And guess what? It wasn't a V8. If it had been a V8 I would've admired it for a minute and kept walking. Instead, I took pictures of it and stared at it for ten friggin' minutes... and it is STILL engraved in my mind. Because it was different.
My point is, you don't necessarily need a big ol' 8 to have a nice ride. Embracing what you have is always a good choice. I bought a hardtop coupe with a 302, and have had multiple opportunities to throw a 351 into it. Instead, I'm keeping the small block and building the car to throw it into corners, since the engine is relatively light and allows me to make a more balanced vehicle. If it had been a 250, I would've kept it as well and made it a boosted corner carver.
If you saw a race between a three-legged horse and a thoroughbred, which would you root for? The underdog. Because it takes balls to do something nobody else wants to do. Takes more creativity to build a car with shortcomings than just slapping together the biggest baddest parts you can afford.
I'm not putting down the guys with big blocks on here, I'm just saying that a little imagination can go a long way. And best of all, you'll dare to be different.
Anyway... WELCOME!!!