Haven't even looked at them, not enough gain to bother with, been there, done
that on the C5s. Down side on some is possible water ingestion for total melt
down. An under drive balancer would be better and would negate the loose
balancer problem if yours has it.

Depends on what you want but the best bet is to have a tuner fit it to your
driving style and desires. That also gives up a base to return to if it up
chucks.

You don't always get what you pay for but that's up to what you want. That can
only be determined by hearing the one you like and get the same thing. Skip the
"X" pipe, waste of money. I liked the Corsa Sport and that's what I got, to much
popping though on the C6 versus the Corsa Indy on the C5s. The "X" pipe cut it
out on the C5 but not the C6.

Wouldn't even bother, not sure the Bose works on my C6, I'll have to turn it on
some time. As far as the GPS I run a separate system that is a whole lot cheaper
and more defined than GMs offering. There are a couple dozen antenna on the C6
without the GPS, not sure how many it would add or how hard it would be to add
them. If your really serious about trying it I'll look it up------- Opps, on
second thought I won't look it up, there's 207 pages on it in the manual. Most
of it shows the pictures without the part numbers unless these are some of the
numbers -- 93807890 module 2, 16832516749 electronic serial number, software
I.D. 146, 0002086783 VCI module. New mounting base required in the windshield
along with heat staking 2 microphones into the header trim, the unit mounts in
the back right compartment with a receiver on the drivers rear wheel hump and of
course in the dash with the GPS antenna. Then there's the amplifier under the
passengers feet, and all of the above ties into the keyless entry and theft
deterrent transmitters and receivers.

Aren't all usnet sites free??? Why would you pay for an account for a news
group?