I would either do Nitrous, as a 5.0 will take a 150 shot and live (done it myself, watch your fuel and timing closely) or save up for a S-trim or H/C/I. the Nitrous is a good way to go, as it is cheap, reliable, and easy to tune for what you want.
I got out of drag racing a few years ago, and built a 302 stock bore 5.0 with the Trick Flow Street Heat top end kit, added a few things, and then dyno tuned it at 300HP and 334 ft Lbs at the tires with heavy ass 18" wheels. The car is meant for open track use.
My point being, build your car so it suits you, and what you want to do. If you want a reliable, fast daily driver out of your 5.0, it will take some planning and hopefully not too many broken parts.
Also, if you get a good quality shifter, like the Pro 5.0, you wont break the trans as often as you think. make shure you get one with the shifter stops.
Just my .02c