yes - to remove the SC from the equation - an after thought was to rephrase the question and ask - why a stock 320 couldnt do 7000rpm....

but then I got thinking.....how about 32Krazy's (Steve) new 996 GT2.....???
"......
In 2000, Porsche launched the Turbo version of the Type 996 for MY 2001. Like the GT3, the new Turbo engine derived from the 911 GT1 engine and, like its predecessor, featured twin-turbos and now developed 420 PS (309 kW). Also like its predecessor the new Turbo was only available with all-wheel drive. A US$17,000 factory option, the X50 package, was available that boosted the engine output to 450 PS (331 kW) with 620 N.m(457 ft·lb of torque across a wide section of the power band. With the X50 package in place the car could make 0–100 km/h (0–62 mph) in 3.8 seconds. This package is named as Turbo S in Europe. Later on toward the end of the 996 life cycle, a 996 Turbo S coupe also returned to the US along with a new debut of the Turbo S Cabriolet boasting even more power— 450 PS (331 kW) and 620 N·m (457 ft·lbff)— than the regular Turbo. The Turbo can reach a top speed of 189 mph (304 km/h).
........"
Plenty of boost and I'm thinking you get these numbers from a 3.6L - I figure its redline capability is what gets it up there (although I havent found figures yet)