Studebaker Dip Stick, 21 1/2 Inch, Used. Item: 2381 on 2040-parts.com

One Lap of the Web: Porsche 959s, the Alfa Romeo 4C and the Mercedes-Benz A45 AMG vs. the BMW M135i

We spend a lot of time on the Internet -- pretty much whenever we're not driving, writing about or working on cars. Since there's more out there than we'd ever be able to cover, here's our daily digest of car stuff on the Web you may not otherwise have heard about. -- When initially produced to satisfy FIA homologation requirements in 1986, the Porsche 959 was the world's fastest street-legal production car.

Opel Astra OPC Extreme debuts before Geneva

The Geneva motor show starts next week, which means we get to see an awesome selection of cars that will never come to our shores. On Wednesday, Opel added the Astra OPC Extreme to that category, which now includes the Jaguar XFR-S Sportbrake, Volkswagen Polo and Aston Martin Vantage N430, among others. The Astra OPC Extreme is 220 pounds lighter than the already-hot OPC, thanks to the use of carbon fiber.

BMW Z4 (2013) new engine and facelift

This is (really) the new BMW Z4 for 2013. Granted, the tweaked head- and tail-lights, and new side vent modelled on the BMW 4-series are subtle alterations at best. It's what's under the bonnet is of more interest, if you've always fancied one of BMW's folding hard-top sports cars on your driveway.