It really doesn't matter as long as it has the tweeter in it with the same connection and screw pattern, it might have to be stock. I really dont want to rewire anything.
Honestly, if they're going to charge you that much, you'd be better off just getting new speakers, possibly even Infinity's made by Infinity. Stock systems with the Harman/Kardon brandnames (JBL, Infinity) usually aren't that great to begin with-there's hardly any difference between the 'regular' stock system and the one with the Inifinty name on it.
Yeah I have thought of replacing them with nre one's but I wanted to same one's just so I could have the same bolt pattern and it would just snap right in, but your right if its that much I could take it to (hell best buy) and get it done cheaper. Thanks