Impatience can be a virtue. Take the BMW featured on these pages. By all accounts, it is a 2004 M3, the 333-bhp wundercar that's taken the world by storm. The only problem is BMW does not make a four-door M3, a situation the crew at Rennsport found untenable.

"I always wanted a four-door E46 M3," said Samir Said of Rennsport.

"The way it looks, however, BMW is not going to do it, not with this chassis anyway. I couldn't wait any longer...I just did it myself."

The BMW 330i is pretty damn close to an M3. Although it lacks the upper-end horsepower, its underpinnings are virtually identical to its more powerful sibling. In other words, it was a great place to start.

The most efficient way to emulate the M3's pronounced aerodynamics was to start with the factory parts. This car was fitted with the CSL front bumper, M3 rear bumper, mirrors, fender flares, rear quarters and a modified rear boot lid.

"We've got about 12 grand into the body alone," said Samir.

"But the components fit beautifully and our paint man did a stellar job with the Imola Red"

The pronounced fenders on the M3 actually serve a purpose besides looking good. They allow the car to swallow seriously big running gear. This car wears BBS LM wheels, measuring 8.5x19 in front and 10x19 out back. Dunlop's SP9000 rubber is sized at 245/35-19 and a gigantic 285/30-19, respectively. This is quite possibly the biggest meat I've seen on a 3 Series chassis. It's got that "steamroller" look other drivers find intimidating.

KW Variant III coilovers have replaced the stock suspension. In addition to height adjustment, the KWs feature adjustable compression and rebound damping for multiple driving situations. Brakes have been upgraded with sizable Brembo units, which include 380mm floating rotors and four-piston calipers.

The BMW's 2979cc, 24-valve six-cylinder mill has been fitted with an ASA SK1 supercharger tuned to run at 6.5 psi. Rennsport's Dynojet has recorded a claimed 350 hp and 320 lb-ft of torque, numbers that place it just north of a stock M3. A Supersprint E46 race exhaust system ensures the inline six has a voice befitting an M3.

Rogue Engineering's short shift kit augments a transmission that includes a Technik 3.38 limited-slip differential.

Rennsport and its sister company Technik Engineering started some 3 years ago. Technik focuses on product development while Rennsport is in charge of distribution."Our goal was to build cars that fill a void in BMW's product line," said Samir. "In addition to this 330ii, we've got a 350-hp widebody Z4, a 450-hp 545i and a few 450-hp M3s."

Although I could most likely live without a widebody Z4, Rennsport's four-door conversion is a compelling one. As much as I love the new M3, I'd love it even more with two extra doors. Last time I looked, an M3 was fetching $50k; a similarly equipped 330i with the Sport package was about $42k. Start doing the math and it's obvious that building what the factory does not can get very expensive.

That's the price of exclusivity.

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