$350 installed? Ouch...I remember when I bought my '98 civic almost three years ago...the remote starter was a $200 option (and EVERYTHING was marked up at the honda dealership, obviously...a 1" (ugly) wing was $700 here! A 1-disc cd player was a little over $500, and I *think* a cd changer was only $100 more). I got them to throw it in for free, since I couldn't get them to budge on the price of the car (paid MSRP).
The point is...maybe you should look around, and see if you can get a better deal...if this place with the high markups only had it for $200 installed, i'm sure you should be able to get a better deal elsewhere...