Tyler,
Glasspacks are cheap and loud. It all depends on what you want the vehicle to sound like.
I have a Dynomax Super Turbo cat back system and it cost me about $150 installed. It is slightly louder than stock, with a nice rumble. The muffler also has a lifetime warranty.
If you're looking for something more aggressive sounding, Flowmaster is a good choice. I'm not sure on their pricing, but I think it is a little more expensive than Dynomax.
Many choose Borla, but I think they are very pricey for what you get. I don't think that's what you are looking for.
There are a number of performance mufflers out there, Gibson, Bassani, Magnaflow, to mention a few. They all sound a little different. Any of these name brand systems are going to be more expensive than glasspacks, as well as more refined sounding, so it's up to you to decide.
I've never heard a 4.0 V6 with a glasspack muffler, so any opinion I have would be imagined. The good thing is that glasspacks are inexpensive, so if you don't like the sound, you're not out much money. They don't tend to last very long, so you definitely get what you pay for. The main thing is getting something that YOU are satisfied with.
Try talking to some muffler shops in your area, someone that deals in performance products rather than Midas or the other chains. A good independent shop ususally has some experience with custom systems. Gather as many opinions as you can, then form your own, because you are the one that will be driving it. Go ahead and get whatever you think you want, don't worry if it doesn't suit someone elses taste.
Let us know what you end up with.
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DOGMAN
91 4dr 5sp
5.5" Superlift