The ADC 212/3, included in the automotive kit, has a maximum speed of 3 million samples per second not 3 Ks/sec. That being said, the maximum sample rate specification has very little to do with the actual sample rates you will experience, at common automotive time bases.
I have a Fluke rated at 25Ms/sec. The 212/3 rated at 3Ms/sec is 62 times faster in normal use.
True sample rate is directly related to how many samples can be 'collected' in the memory buffer. The larger the buffer, or Record length, the more samples you have for a given sample period. Longer time bases reduce sample rate and shorter ones increase it.
You can compare scopes by dividing the number of samples collected by the time of capture in milliseconds to get the requested sample rate in KHZ. You have to know the buffer size before you can compare one digital scope to another. If the manufacturer won't give you this information, then they either don't know, or are too ashamed to tell you. Either way, it's not a good thing. Move on.
The 212/3 can collect up to 32,000 sample on one screen. The Fluke mentioned earlier only 512.
I checked the ATIS site and found no specs for that scope.