WHITEFISH, MT -- "If I buy a minivan, my life is over." That's the psychology General Motors Corp.'s Pontiac-GMC Div. is trying to use to its advantage with the new "Montana" version of its Trans Sport: a burly looking minivan that tries hard to look like a sport/utility vehicle and shed the dreaded "mommy-mobile" image, while not treading on GMC's truck turf or competing with Chevy and Olds siblings.

The Montana Package -- expected to make up at least 65% of Pontiac's total minivan sales -- essentially is a Trans Sport with more aggressive-looking plastic side cladding, bigger tires and stiffer suspension, but it means far more to the marketplace -- and GM.

To consumers, it's the first attempt by a Big Three automaker to fit a product into a new niche: minivans and station wagons for baby boomers who need them but hate the idea of owning one. The trail has been blazed by the successful Subaru Outback wagon.

But within GM, the Montana also represents one of the first examples of brand management at work.

Brand management has only been officially in place at GM for about nine months, but Pontiac has been using the concept for at least three years and some argue Pontiac has been successfully using the basics of brand management since the early '80s. Its image as the seller of GM's performance-oriented vehicles now is probably the clearest and best-established of all of GM's units.

No one is more enthusiastic about the concept of brand management than Pontiac-GMC General Manager Roy S. Roberts. "There is more information, more knowledge. We have better strategies in place than I have ever seen In my career," he says. However, his goals are even more ambitious -- and a bit scary. He cites Harley-Davidson as the ultimate in so-called"brand equity," and says Pontiac-GMC will only know true success "when our customers tattoo our brand on their bodies."

Trans Sport Brand Manager James D. Murray isn't yet talking about tattoos, but he says brand management has introduced a scientific aspect to marketing and product development that was lacking before. Market data always has been available, but it often wasn't used. Mr. Murray won't say it, but top executives are infamous for insisting on last-minute design and engineering changes to suit personal tastes and little else.

That won't happen anymore without justification. When someone suggests a change "The first question is: `Where is the data, what does the research tell us?,'" Mr Murray says. "In the past, those questions weren't asked."

Without this special kind of research and discipline the market niche for the Montana Package probably wouldn't have been discovered a few years ago--before the SUV market was white hot. "As recently as three years ago, we thought Montana would be 20% to 25% of Trans Sport sales. The more customer focus groups and research we did, the more confident we became that increasing the percentage was the right thing to do. Now we might get to the point where the Montana is 75% to 80% of business,"