I fullyagree with Marty here
^.....
And now the reasons why.....
First, I've had the factory stock 3.55's in my Marauder, and then I changed them and installed the 4.10's myself, and about 6 weeks later I then removed the 4.10's and installed the 4.56 gears (again, by myself).The 4.10's weren't enough for me with a Naturally aspirated Marauder. So I know for a fact what three gear ratios I had in my Marauder, since I counted the number of teeth on both the ring and the pinion gears of each gear set myself, and did the math before I installed them. So there were no mistakes about what gear ratios I had. And that was done before my car was supercharged.
I also took my car to the track back then and used the g-tech device on the street as well to compare the before and after times of each modification. And let me tell you that from my own experience with all three gear ratios on a Marauder, yes, the 4.56 gears kick butt and are the best on the dragstrip, and are also the best for smoking the tires from a mere dead punch on the street with a NON-supercharged Marauder. But there's always a price for all-out performance. And with the 4.56 gears that price is that you'll lose a little bit of your top end above 100 MPH. Now that might not make much difference to you since there isn't any great need to be traveling at speeeds of over 100 MPH on the public highways, but that's purely for you to decide since it's your car, your License, and you life.
Second, don't even think twice about 4.30 gears since you already have the 4.10's, because there's no way on this earth that you're going to be able to tell any difference on the street between 4.10's, and 4.30 gears, because there's so little difference between the two. That difference is so miniscule, that it would only make about one or maybe even two tenths of a second difference in the quartermile at the track if you're lucky, and you're simply not going to notice that difference in the "seat-of-the-pants" G-force feeling while driving your car on the street.
To illustrate my point, let me point out to you that with the stock tires on a Marauder equipped with 4.30 gears in the rear, you're only going to be reving at 120 RPM's more at 70 MPH in O/D than you would be with the same car and same speed in O/D with 4.10 gears. So if you think that a mere 120 RPM difference at even highway speeds is going to give your drivetrain and engine more mechanical leverage to make the car move faster off of the starting line to a point that you'll actually notice any difference just by the way it feels when you hit the gas pedal, then I'm sure that someone has a bridge to sell you too. No offense my friend, it's just high performance car reality I'm talking here.

In fact even with the O/D button off and with the transmission in 3rd gear on the highway traveling at 70 MPH, your Marauder engine with the 4.30 gears will still only be reving at 160 RPM's more than with the 4.10 gears. So the tiny difference isn't even worth you running out and spending the money for another gear set. Anyone who tells you that it would be, is.....well, I'll be nice, and leave it at that. I'm not telling you that it's wrong nor that it's worthless for anyone to choose 4.30 gears for their Marauder, but only that it would make such a small change in 4.10's to 4.30's, that it isn't even worth your effort to change your choice of 4.10's now that you've already made that choice.
Now, one more thing.......I get the impression because of your choice of words in your post that your expectations are waaaaay too high for these minor modifications that you're talking about (just as mine were at one time before my car was supercharged). I'm not trying to burst your bubble nor disappoint you, but you're in for a big disappointment as it is if you're expecting to obtain "some insane oomph" from your 4,200 LB Marauder simply from a gear change, or an under drive pulley set, and a cold air intake. With all three of those you'll notice a difference in your before and after ET's at the dragstrip (maybe going from low 15's to low 14's if you're very lucky) which isn't bad, but you're not going to feel a major colassal change in the way your car moves just by driving it on the street in the way of acceleration G-force. So don't expect the car to feel like a whole different animal, because it will not.
Atleast two of these modifications that you mentioned in your post are worth the money, so don't think I'm trying to say that they aren't. But you need to keep your expectations realistic. The fact of the matter is that HP and performance costs money, and if you want to go real fast, that simply isn't cheap. You only get what you pay for in the automotive Hi-perf game. Don't think that you're going to put $1,000 into your car, and turn the thing into an animal unless maybe you buy a Nitrouis oxide injection kit ofcourse. Which is the only thing that will be close to that cheap and add some serious "insane oomph" to your car. (although that will also come with the added inconvenience and expense of having to fill the bottle every week with a daily driver, which BTW cannnot be done at just any gas station).
An underdrive pulley set will add no more than 12 HP at the wheels at best, and that alone will not be felt. If you're going to add that to a few other mods, then some people might consider that worthwhile. But all alone, it won't be noticed on the street. I haven't anything to sell you, and I'm simply speaking to you as a fellow board member based on my own extensive experience of modifying my Marauder as well as other V8 RWD American cars. So I haven't any reason to tell you these things other than to help you remain realistic about these minor modifications, in hopes that you will not be disappointed later on, after spending your money. So I'd stay with the 4.10's if i were you, and if you're going to bother making another gear choice, then go with 4.56's if you want something that will really make a bit of differnce over and above the 4.10's, because the 4.30's simply won't feel any different.
You might get away with the factory driveshaft with the 4.10 gears w/out it vibrating ( I did), but you'll know it if it's vibrating. It's something you cannot miss, and your passengers will notice it too, but it might only occur at very high speeeds if at all. Marauder driveshafts are longer than Mustang driveshafts and many other cars as well, so they can get "Loopey" during high RPM's (driveshaft RPM's I'm talking about). but you definately won't get away with the stock driveshaft with 4.56 gears (incase you ever contemplate using those). I wish you the best, and I'm here to help. If you ever do decide on 4.56's and are willing to make that compromise in top end performance, write to me first, because there's a special $34 part you'll need for that gear ratio that isn't needed for 3.55's, 4.10's, and 4.30's. And I wouldn't want you to find that out the hard way (like I did

). sorry for this post being so long, but I wanted to try and answer all your questions, and I do get intense about ring & pinion gear ratios. It's one of my favorite subjects.