Re-birth takes different strokes of genius.

In the 1980s TV sitcom hit, "Diff'rent Strokes," Arnold and Willis Jackson, played by Gary Coleman and Todd Bridges, came to live in a Midtown penthouse with a rich single dad after growing up poor in Harlem.

Perhaps, in the not-so-distant future, the storyline would have them relocating to a penthouse--but staying in Harlem.

The second renaissance in Harlem is well underway and is reflected in retail, residential and to a lesser extent, commercial development.

Retail-wise, it's still not fair to compare Harlem to Midtown, due to the sheer numbers of people who come through Midtown every day.

"Midtown has such different dynamics, as so many bazillion people come into Midtown from elsewhere," said Steven Barshov, a real estate attorney who, along with his wife, Suzanne Joyce, provides guided bus tours of various New York City neighborhoods for real estate professionals.

But the 125th Street corridor, including the Harlem USA mall, is now chockfull of chains, to the point where it can be compared to another attraction. A more realistic comparison, Barshov said, is to Fulton Street in Brooklyn, another well-known shopping drag.

"I think, overall, 125th Street has fared a lot better than Fulton Street in Brooklyn," Barshov said. "The retail has been quite strong, in fact. It has caused some concern in the Harlem community. The local businesspeople are having a harder time finding space on 125th Street.

"The fear is that as 125th Street flies, the rents will climb so high that the main retail tenants will be national franchisers and chains," Barshov added.

This would not work in favor of those restoring the city who still intend to take care of its natives and preserve its heritage.

Fortunately, the slightly less mainstream areas still carry local area flavor, sometimes in an upscale fashion.

Settepani, a pastry and coffee store, at 196 Lenox Ave. (Malcolm X. Boulevard), maintains an atmosphere decidedly more fancy than Starbucks, selling gourmet cakes, danishes, spreads and beverages.

And ethnic restaurants are abundant in Harlem, as are reminders of culture. The Boys Choir of Harlem and the Apollo Theater are longtime mainstays.

Meanwhile Harlem will venture into new commercial territories with the upcoming arrival of a Harlem Auto Mall on the East Side and a new Marriott hotel, the first Harlem upscale lodging facility in decades, across the street from the 125th Street railroad station.

Former President Bill Clinton's 125th Street office is relatively alone in a local office market that primarily serves government and not-for-profit agencies. But this could change, according to local broker, Lorina Torres, of Torresco Realty.

The zoning codes in an area along Third Avenue have recently been upgraded, leaving open the possibility of upscale office space.

"We've managed to achieve upzoning to R8a on Third Avenue," she explained. The floor area ratio for the floorplates is six times the size allocated for the footprints.

With these plans, she said, developers might be able to lure an occupant "that would change the market that is limited now to government and not-for-profit agencies."

Meanwhile, part of taking care of the native Harlemites involves constructing affordable housing, an area with which Perry Cohen, a real estate attorney with Todtman, Nachamie, Spizz and Johns, is well familiar.

"I've seen a large amount of pioneering going on and people saying, "You know what? I want to stay in the city. I'm going to get much larger for my money than before."

Consequently, Cohen said, a migration has taken place to Harlem from the Upper East Side and Upper West Side.

"Large amounts (of people) from the Upper West Side are moving up there and getting 3000 s/f units, as opposed to 1000 and 1500," he said.

But thanks to new luxurious amenities in the new Harlem developments, the migrants can still find amenities, such as a nice marble lobby, a doorman and granite countertops.

"The developers I represent, with all due respect, aren't compromising," Cohen said.

But the new luxurious Harlem housing places a strain on those who have been able to live in the neighborhood for years. That's where Cohen and others come in.

Cohen has represented developers in the construction of the Cornerstone and Cornerstone II housing projects as well as the Rosa Parks housing development on St. Nicholas Avenue.

The Rosa Parks development will be opened with a ribbon-cutting ceremony April 15. Parks' daughter, Elaine Eason-Steele, will be present to honor the development named for her mother, a civil rights legend.

Cohen credited the work of Borough President C. Virginia Fields and several developers, who "ran out of opportunities in Soho and Tribeca" in helping a "bad neighborhood" to rebuild into a cultural phenomenon.