Salvesen won't say exactly how he did it, only that the increase had more to do with manipulating the building codes than with the actual size of the location. "A nightclub takes anywhere from a week to six months to get approved," he says. "You have to file construction permits, plumbing, mechanicals, sprinkler systems, electrical . . . and we don't even get involved with Liquor, Health, or Consumer Affairs."

Had Marvisi needed a new location, he would most likely have called Alex Picken, a commercial-real-estate agent and former D.J. at Red Zone who systematically scouts for possibilities. New establishments generally open only on the site of previous ones, since existing dance clubs already have a cabaret license, the hard-to-qualify-for permit that the city insists upon for every premises with dancing. "In recent years, the only new cabaret license to be granted in midtown that I can think of was for the China Club," says Picken. That's why he keeps a list of all the existing cabaret licenses in the city (there are currently 142 in Manhattan and 697 citywide), as compiled by the Department of Consumer Affairs. In his spare time, he cold-calls preexisting clubs with licenses and asks them how they're doing.

Noise complaints your problem? Give a holler to Al Fierstein, a professional acoustic consultant who makes the bulk of his living telling clubs like the Tunnel and the Roxy how to keep quiet. "Some of the measures I use -- and this varies in every case -- include putting up extra Sheetrock, lead lining for the walls, baffling on air-conditioning systems, concrete-block walls and sand-filled walls and ceilings, sound locks so noise doesn't travel around doors into the street," he says.

The savviest owners, however, also take their own precautions. The proprietors of Chaos, a trendy nightspot on East Houston Street that opened last month, tout their indestructibility nearly as much as their South Beach vibe. "This is a dance club without a real big dance floor," says co-owner Tony Theodore of a domed room dripping in red velvet. "Every piece of furniture in this space, every table, every couch, is structurally designed to be able to withstand somebody dancing on it. The chandeliers are high enough away. The curtains are bolted into the rods." Adds Theodore's partner Michael Ault: "Everything is puppyproof and fireproof, and we've got guards everywhere."

Back at Exit, David Marvisi, dressed in head-to-toe black, slumps in a banquette at the back of his club and ticks off other hassles with the antenna of his cell phone. Zoning changes, which have empowered residents in commercial and manufacturing neighborhoods to register noise complaints, resulting in fines starting at $4,000. Disorderly-premises violations, issued in any instance that Marvisi has to call in the police. Even his club's name reflects the current compliance mania, especially with egresses. "Every time I look up, I see another exit sign," he says, "so I figured it would be the best name."

Once, being a partner in a nightclub was viewed as the ultimate ticket to city society, a stylish sideline desired by every swinging young banker with a $500,000 bonus. The hipster cachet is still there, but even for a businessman like Marvisi (who made his fortune in the Uncle Steve electronics empire), being part of the game exacts a steep price. "What it takes," he says with a sigh, "is money and time."

More and more, that money is being diverted from the more glamorous elements like celebrity D.J.'s and posh VIP lounges. Of the $9 million that Marvisi pumped into Exit's renovations, $250,000 went to soundproof the club with triple layers of Sheetrock and a specially designed metal-and-plastic ceiling, and another quarter-million bought a cutting-edge in-house video security system. His 70-man security staff, all of whom must be EMS-certified -- including the five guards who patrol the 300-foot perimeter outside the club during operating hours -- costs him $9,600 per night.