On North Shoreline Boulevard, just south of the Cinema 16 movie theaters and the city's busy industrial parks, is restaurant Fiesta Del Mar, which opened in 1991.

During a recent lunch hour, the parking lot is full and customers line up outside the door. On the wall are 200 different kinds of tequila, and on the menu is Mexican food of a variety hard to find anywhere else. The family-run restaurant is in full swing.

Voice readers have chosen Fiesta Del Mar as the best Mexican restaurant in the city for the last several years. But despite its success, the restaurant may only be around for another year or two, when a new owner plans to redevelop the site for office space.

Why one of the city's most popular restaurants is being turned into office space, with so much already available in Mountain View, "certainly has been the question mark in our minds," said co-owner Susie Garcia.

"We've sort of been on a roller coaster emotionally. We thought we were just going to rebuild, but business is business. The developers aren't bad guys. The site certainly needs [to be redeveloped]," she said.

Originally, the property owner planned to turn the site into a retail space with a Starbucks, a Panda Express and room for a new Fiesta Del Mar, Garcia said. An office building adjacent to the restaurant was to be razed to make way for the project. But suitable terms could not be reached, and the plan was scrapped due to lack of parking and delivery truck access.

Julie Hawkins, associate planner, confirmed that two different plans have been submitted, one for retail and one completely for office, though no further details were immediately available.

Gilberto Figueroa, restaurant manager, said his family is already considering moving the restaurant to another location — possibly to Sunnyvale, where they have been welcomed by the economic development department, Garcia said. The family already runs another version of the restaurant in downtown Mountain View — Fiesta Del Mar Too on Villa Street just east of Castro Street.

But Garcia said she would like to remain in Mountain View if possible, because that's where the restaurant got its start and where its loyal customer base is. Ideally, she said, it would be relocated north of Highway 101, a little bit closer to the theater complex and companies such as Google, whose employees frequent the restaurant at lunch time.

The Voice received e-mails from many customers saddened by the possibility of losing the restaurant, including one from Belgium and another from Benicia.

"The service and food quality is unparalleled at any other Mountain View establishment in this price range," wrote local resident Valerie Ann Bubb in an e-mail. I just don't see how the smaller Fiesta downtown could attract the same people here. The Shoreline location is just so convenient for people coming from all over the Bay Area — I even saw [former 49ers quarterback] Steve Young dine there once. I'd hate to see this replaced with another Chipotle and Starbucks complex."

In other e-mails, sad customers talked about the restaurant's ambiance, the family-style service, the quality of the food and traveling from afar to enjoy it.

"I have never had a better Mexican meal, anywhere," wrote Amy Hastings, a resident of Dublin, Calif.

"I quickly became hooked on the mole poblano burrito and now can't go long without my 'mole fix,' wrote Melissa Scheel.

"I am due to be visiting the Bay Area in February, and if FDM is gone then I shall be both peeved and disappointed," wrote U.K. resident Alec Muffet.

Scott Morrison works in Menlo Park, lives in Castro Valley and finds the location near Highway 101 ideal for meeting friends. "I can't tell you how many birthdays have been celebrated there along with our Christmas get-togethers," Morrison wrote in an e-mail.

Another customer, Freedom Moore, said he frequently asks the restaurant staff, "Where will we eat when you close?"

"They always respond, 'At Fiesta Del Mar,'" Moore said. "I believe this to mean that they will find a new home for our friends and family."

The chosen developer for 1005 N. Shoreline Boulevard is Haury Properties, a large San Jose firm with several retail and office developments planned for Mountain View. The firm was not available by press time.