Hi, contrary to what KennyV said, in my own opinion..Quantum Pickups are quite good compared to many other stock pickups. It is somewhat comparable to Schecter Diamond series, which are very good too.
Alexanzer, you should remember that elec.guitar sounds and tone don't come only from the pickups. If you are thinking of a huge different. This will probably not the way. Keep in mind, I said "probably" because in my experience..many pickups react differently with amps, set-ups, etc. But most of the time, it is just subtle.
Amps, cables, pedals and even your guitar set-up can make bigger impact on your tone.
For instance, I don't know why you bought it at first if you don't like the pickups at all.. Have you tried it before buying? If you have tried it and it sounded great and that was why you bought it. Then, the problem may lie in your other equipments, not the guitar itself.
Please remember that your guitar setup (string action, Intonation, Pickup height) may also affect your tone...a lot!!!
When I started playing guitar, I wanted to replace my pickups because that was what all people said to me..but after I learned a bit about setups, most of the time, I felt that probably I didn't need to replace them..the tone diff is not that far!!.and so, I left the quantum pickups in my guitar.
So, please experiment with those..there are so many videos on youtube about it these days...it is fun.
For me, I don't like the tone zone very much..air norton and tonezone are standard for Ibanez prestige these days...so, many people have changed those pickups too...my advice is to search info and demos about several different pickup makers if you decide to change it...find which pickup that gives u a distinct quality different than your quantum.