There's tons of threads about GSA tank bags. Seems they're about as personal as seats
I've put just about every tank bag on that's out there with the exception of the Bags Connection bags. I assume you're talking about the BMW bags, but which size? The large is very cavernous and I sold it after it was installed. It was like having a duffle bag on my tank. The small bag is decent, but the plastic map case is very thin and has a reputation for yellowing on the BMW tank bags. If you're gonna spend that kind of $$ on a tank bag (BMW), I'd look closely at the Touratech bags or the Bags Connection GS bag. I'm cheap so I always bought my bags used at half of retail. That's probably why I haven't bought a BC bag because the mounting ring is $75 alone for the newer GS bikes. My GSA is sporting the TT Day Trip bag right now and I'm very happy with it. The great thing about the TT bags is the bottom is molded to the GSA tank so they don't slide around like many of the other brands.