The chip was $395. Installation took about 1/2 an hour. Getting the module out is easy. Getting the EPROM out of the socket is the most time consuming part. You need a small torx driver, # 10 I believe, to get to the EPROM inside the computer module.
I don't have any exact figures like from a G-Tech, but after the superchip, it did feel stronger, expecially in the upper RPMs. I am thinking about getting a G-Tech off of eBay. Then I will do some runs with the Superchip and without.
I never really had a sulfer smell after hard driving. So it is hard to say.
Hope this helps.