I would advise against the KS600. Although they are a little cheaper on price, the tweeter is on the mids and you will have a non functional tweeter on you're door.
IMHO components are separate for a reason. The waves from the mids disrupt the sound emanating from the tweeters which do not sound as clear as a true component setup.
Get the KS60.2 (or 08KS60.2) as they are component speakers that have detachable tweeters. Meaning that if you ever take it out you can put the tweeter on the mids by taking the middle part out and replacing with the tweeter.
In any case, at the lowest setting the highs are so high pitched and strong you can always put the tweeters back to the lower part of you're door and take the stock tweeters and put back on the door for decoration.
Get the components, it's a better upgrade. Just did my install and it slipped right in. The tweeters can go straight in without the mounting stuff and it looks recessed into the tweeter housing. It's great since it would never get in the way.
The speaker grills look really cool too.
They have a 75W RMS rating (the only rating you should look at) so if you are planning on putting more strength then you should be able to go with the RS60.2 (higher end) but the depth of the speaker is a little bigger, it "should" fit the Viper's door.
In my opinion, the KS60.2 is still not good enough. I have a 12" sub in the back (easily can be taken out) as well as an amp powering the sub and speakers up front with an Alpine IDA-X001 head unit to my iphone/ipod.
The sound is great but I still prefer the sound of a nice luxury car as it sounds complete. This one lacks mids (still) as the treble and bass are very strong and with the exhaust/headers making more music, the mids kind of dies in the background.
If you can try the RS and fit it, do it. You do not have to have a discerning ear to notice the difference. Anyone can. Spend the extra dough if you can.
Fitments can be checked on the Kicker site:
RS60.2 Highly recommended but check fitting on depth. I know GTS doors have a 2.5" room for a deeper installation.
KS60.2 Direct fit guarantee as I am using it right now. Installed yesterday.
KS600 (coaxial) Ill-advised
Will post pics upon request.