SPRING HILL, Tenn. (AP) _ This tiny farming community exploded into a boom town Monday as General Motors Corp. announced plans for its $3.5 billion Saturn complex here.

Within two hours of GM's announcement, Rachel and Campbell Haffner said they received $250,000 for a white-columned antebellum home for which they paid $30,000 for a decade ago.

''I've never been through anything like this. I'm 57, but I've aged 10 years after this,'' said Mrs. Haffner, a life-long resident of Spring Hill who opposed the plant's coming here.

Tennessee Gov. Lamar Alexander termed the selection of Spring Hill ''a national verdict.''

''It establishes Tennessee as the best home in America for tomorrow's jobs,'' Alexander said in Nashville. ''We will, all of us, do everything we reasonable can to help make Saturn a big success.'

General Motors said it tentatively selected this community of 1,100 people for the project, which is expected to generate 6,000 jobs in the plant itself and another 20,000 jobs in related businesses. Construction of the plant depends on discussions with state, local and utility officials, GM said in Detroit.

Not everybody has been pleased with the prospect of the plant's arrival. Dairy farmer John Campbell said Saturday that Spring Hill doesn't need what GM has to offer. He said he was approached last week by a real estate agent seeking to buy his 525-acre spread.

''I just told him it wasn't for sale. I told him we didn't need too much progress down here. I told him, 'You real estate agents have gone mad,' '' said Campbell. ''What if it turns out to be an Edsel?''

Other Spring Hill residents, however, reacted with glee and trepidation after GM ended weeks of speculation with Monday's announcement.

''We're very glad. I feel it will be a great asset to the community,'' said June Quirk, Spring Hill's city recorder. ''Spring Hill needed a good change and this is it.''

Televisions were on across Spring Hill as townspeople awaited the GM announcement.

Resident Susan Brown, 39, said she put her home up for sale three days ago.

''I've been haggling with the idea for some time, but it was just the time to sell,'' she said. ''It (the plant) is a scary feeling but probably good overall.''

''I like Spring Hill just as it is, but you have to have progress,'' said Ona Little, part owner of Kirk's grocery. ''I hope they don't tear down the house. I'm not smart enough to know just what the plant will do to the town. I can't think that big.''

Alexander, meanwhile, flanked by legislative leaders, met with reporters and unveiled a blue-and-white sign reading, ''Tennessee Welcomes Saturn.''

House Speaker Ned McWherter, a Democratic candidate for governor, said the GM announcement marked ''the greatest day that I guess some of us have had since we have been in the public forum. We're proud of this company coming to our state.''

In addition, the state is actively seeking a third auto plant - a U.S. facility to make midsize passenger cars for Japan's Toyota Motor Corp., Alexander said.

''I know something about Toyota, but I don't ever talk about our industrial prospects until they're ready to announce their decision,'' he said.