Sweet deal for $300!! Like other's have said... it's your car, do it however you want to. In my humble opinion, it's not worth keeping it stock without the numbers matching drive train that the car was born with. And there are a lot of engine options that are more fun than a 318. Not that there's anything wrong with the teener motors, but the 360 and 408 strokers can be beasts.
When you close your eyes, what do you see? Color? Wheels? Trim? Let's hear some of your plans, outside of prostreet.
Also, go on EBay and search MOPAR A BODY in parts and accessories. Not that you will buy anything on EBay, but you will find 30+ pages of parts/ideas that you don't know exist yet. There are a lot of "upgraded" Mopar parts that offer an improvement over the original design.
Get on the mailing list for companies like Mancini Racing, Speedway, Laysons, QA1, etc. They will send out coupons or have sales every once in awhile. The savings can add up if you have patience. There are some vendors that are members on this site, and some offer us discounts.
Most of all, ask questions. No matter what the question is, big or small. There are so many knowledgeable people on this site, it's scary. No question is too basic. I had to ask a question about a bolt that I didn't recognize. I got 3 answers within an hour or so.
Last thing, start a build thread. Not only so other FABO members can keep up with your progress, but it's a great way to keep an archive of your build. In case you ever sell the car you will have documentation. Plus, in a year or two from now it's fun to look back and see how far you've come.
Good luck.