tubedude, get a kit. I was in the same position as you, I had another instrument I was good at. I always wanted to play drums. So I figured, I'd start off small, get a snare, or a snare and bass and HH. The only used set at the place was the whole thing. It was cheap and more than I THOUGHT I needed. I would have gotten totally bored with less than the whole kit. I never would have gotten anywhere on less.
And, I can hear the difference between snares in the store, but I'm not enough of a drummer to know what I like better. I could have a $80 snare or a $500 snare and I couldn't give a damn which one I was playing. Plus, I have to mute the hell out of it b/c it's so incredibly loud. It took me months to be able to listen to the kit w/out headphones, or those cans that you wear when you're firing a shotgun, the big-ass red mofos you see now on the 'landscapers.'
My foot is a brick. I have to work very hard on my right foot, if I hadn't started right away with the kick drum, I'd be even farther set back than I am already. Yet as a guitarist, my right arm is solid. I never even tapped my right foot to music, I tap w/ my left heel, or right heel. It's like day one w/ my right front of my foot. W/out a kit you won't know what you really need to work on. Yes, learn rudiments, but apply them to the kit. An active snare drum isn't the priority in most rock music, you know that. Everything everyone else said is valid, but dude, get a kit and get a kit soon and spend it on the kit, NOT some snare drum that is meaningless until you know what to hear, how to tune it, etc. I have 6 different mics to record my
acoustic guitar with, I can barely decide which one of those I like better, I'll never figure out what snare drum I'd like b/c I'm not a drummer. If, ever, somehow, I ever become a drummer, then, maybe, I'll know enough to care about what my snare drum sounds like. Take it in steps. Or, maybe you love that snare drum and you know what to choose, then good for you, but I'm just giving it to ya IMHO. Good luck, you'll progress fast as a motivated adult already familiar with music.