Porsche AG is offering more equipment on the Boxster model, and keeping the sports car’s earlier design, to fend off competitors including Bayerische Motoren Werke AG.

“There’s no reason to make radical design changes on the car,” said the chief executive, Wendelin Wiedeking, in an interview in Poerthschach am Woerthersee, Austria. “We’ve always aimed for perfection through evolution, not revolution.”

Sales of the 8-year-old Boxster have fallen every month for the past year in North America, the company’s largest market, as BMW’s Z4 sports car and DaimlerChrysler AG’s Mercedes SLK models have taken customers. The revised Boxster follows Porsche’s introduction in July of a new version of its other sports car, the larger and more expensive 911 model.

“The new 911 and the Boxster models look more like facelifts and I’m more cautious than optimistic about how successful those two models will be,” said Martin Sachsenmaier, a fund manager, who manages 500 million euros ($617 million) at Frankfurt Trust, which owns Porsche shares. “Look at what happened with the face-lifted Boxster of a couple years ago. It did virtually nothing for sales.”

Porsche has priced the car at 43,068 euros including value-added tax compared with 42,256 euros for the previous version. The company has added an air conditioner and radio as standard equipment. The new equipment is the equivalent of a 9% price cut, Porsche said. The model goes on sale on November 27.

Shares of Porsche have risen 12% this year, beating the 2% gain in the CDAX index of Germany’s 696 largest traded companies.

Mr. Wiedeking has boosted earnings 10 years in a row at Porsche, helped in the past two years by the Cayenne sport-utility vehicle, introduced in 2002. The Cayenne supplements demand for the company’s sports cars in America and Europe. Stuttgart, Germany-based Porsche said last month that fiscal 2004 pretax profit exceeded 1 billion euros, a record.

The Cayenne and revised Boxster will probably accelerate earnings growth at Porsche said analysts at Credit Suisse First Boston in London, Mike Dean and Harald Hendrikse, in a note to investors. The analysts raised their rating on Porsche stock to “outperform” from “neutral” and increased their stock price forecast 16% to 625 euros a share.

The new Boxster comes in two versions. The basic model, with a 2.7-liter engine producing 240 horsepower, is more powerful than its predecessor and accelerates from 0 to 100 kilometers (62 miles) an hour in 6.2 seconds. The high-performance variant has a 3.2-liter engine and a top speed of 268 kilometers an hour. About 80% of the parts used in the car, including ceramic brakes and the retractable roof, are new.

Porsche two years ago reworked the Boxster by increasing the two-seat convertible’s engine power, changing the design of air-intake valves in the front of the car and raising the fuel efficiency. It also added a glove compartment and a cup holder.

Design changes to the new model include increasing the diameter of the wheels by one inch and making the air intakes larger. The car weighs about 20 kilograms (44 pounds) more than its predecessor because of added equipment, including a radio and a climate control system, which is now standard.

The Boxster’s development was initiated by Mr. Wiedeking to expand Porsche’s brand to become more affordable and attract more customers at a time when the German company was unprofitable.

“The Boxster brought us back to profitability,” said Mr. Wiedeking. “Without this model, the development of this company would have been completely different.” The company expects another record year of sales and profit growth in the current fiscal year ending July 2005.

After a record loss of 76.8 million euros in fiscal 1994, Mr. Wiedeking even considered designing and selling an entry-level four-door car for the Chinese market, priced below $10,000. Porsche got conditional approval from Beijing for the car, whose chassis was to be almost a foot off the ground to cope with Chinese roads.

Instead, the chief executive opted for an entry-level sports car, based on the original 356 and 550 Spyder sports cars. Porsche is aiming to sell 15,000 units in the first full year of production from a peak of about 27,900 in fiscal 2001 and will “certainly” reach that target, said an analyst at Landesbank Rheinland Pfalz, Michael Punzet.

“It looks very similar to the old model and even looks a bit more like the 911,” said Mr. Punzet who has an “under perform” rating on the stock. “The design is very Porsche-like.”

Boxster customers are largely new to the Porsche brand, since the car is less expensive than the 911, said Mr. Wiedeking. There’s no cannibalization, or shifting of buyers from one model to another, between the 911 and the Boxster, he added.

The car will be made at Porsche’s plant near Stuttgart and at Valmet Automotive Oyj’s factory in Finland. The car contributes about 5% of the German company’s earnings before interest, tax, and amortization and helps the company spread development costs, according to an analyst at WestLB, Fredrik Westin.