Passive 8600 Advice Needed

[InfBlue]

Hi,
I want to switch up my ASUS 256MB 8600GT with something quieter (I've already found someone who will buy it). It looks like I have four choices (based on location, links are newegg though):

Gigabyte 8600GT Silent Pipe 2
Gigabyte 8600 GTS Silent Pipe 3
Asus 8600 GT Silent
Asus 8600 GTS Silent

I'm personally biased towards the Asus cards as I've never had an Asus component fail on me, but the heatsinks on their cards seem to be obviously inferior. If anyone has any experience with these cards, I'd love to know.
The other thing I want to know is whether buying an 8600GTS is worth my money. If I overclock a GT to close to GTS speeds (which I'm pretty sure is possible, correct me if I'm wrong) am I going to get similar performance?
Either way I'll probably upgrade to an 8800GT once a decently priced passive card makes its way to Canada (lets say about 8 months from now).
So, advice and opinions anyone?

 

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If you ask me, is passive cooling worth that much to you? Some of those 8600GTs are pretty expensive; there are ATI HD3850s for around roughly the same price as the higher-priced 8600GTSs but they absolutely KILL them in benchmarks.

 

[InfBlue]

The big problem is that I'm in Canada. I still haven't even seen an 8800GT by a recognizable manufacturer for sale yet. The passive cooling is worth that much to me - otherwise I'd stick to my 8600GT. I'm going for a silent computer, so I'm trying to eliminate fans or replace them with low RPM 120mm fans. Are there likely going to be many passive 3850s? I have no idea what their max wattage is.