EMG's in my spector

ok heres the deal..

I have a early 90's spector that was made in korea. Its a neck-through. I really couldnt find much info on this bass, but i'm learning more all the time. The pickups are covered and say spector on them in gold. I was originally told these were active spector pickups but i don;t think they are. I know it has an active preamp, but i'm thinkin about replacing the pickups with sum brand new active EMG's. IF i do that i have a few questions:

1. will it drastically improve my sound
2. How much and where can i get a set
3. which set do u reccomend (Its a P-J setup)
4. will these active pickups add another battery?
5. Do u reccomend adding a different preamp to these pickups.

All in all i love the bass but i was told that this bass is identical to the USA NS-2's except for the pickups, so i want to get damn close to that USA sound. Thanks in advance guys.

 

thanks alot for the info nino, it was a big help. When i said that it was i identical in looks and design. I mean i know its not the same wood or craftmanship, but i'd imagine its roughly the same body design and neck length and such. Sorry thats like saying those OLPs are the same thing as my stingray, i didnt fork over the big bucks for US spector so i don't get the quality. I would have to say for the price though its an amazing bass. thanks again when i get sum money or xmas comming up i will put in a set.