UE600 tips come with Logitech UE600/600vi. They should be selling at $10 on Logitech website. Amazon sells Sony hybrid tips.
No, I'm talking about the original ones.
I am not a fan of Comply tips except for some treble happy IEMs. They decrease the treble too much for my liking.
From memory BA200 has more recessed midrage compared to IM50/70 forward midrange. Bass hits harder and bigger on IM50/70 while it is lean and softer on BA200. I think it will be an ugrade from BA200. They are quite different sounding IEMs.
I find the sound to be a bit muffled and veiled with the stock tips as well. If you're going by RadioShack, see if they have some Auvio hybrid tips. Those are my preferred tips and help open up the treble and cut down on the bass boom. It won't get to the detail level of VSonic treble or anything, but wider bore tips like the Auvio will definitely help with that veil. You could also try removing the filters like Ozkan is fond of, though I leave mine on. These are the Auvios: http://www.radioshack.com/auvio-silicone-replacement-tips-medium/3300784.html#.VHNMxYsZ5UQ
Perhaps we should start a premium silicone tip company!
I love the fit, isolation and comfort of foam tips too, but having to replace them every few months just makes it unappealing, not to mention the foam tend to get gross faster. Still, my last pair lasted 5 months then on the second wash it started peeling off.
The Auvio may be a little bigger, but they're the same general size.