available for both N54 & N55 335i vehicles, it was easily verified if a vehicle was equipped with the PPK as during installation stickers that read "BMW Performance Power Kit" were placed near the air intake on all equipped vehicles, the N55 equipped 335i vehicles also featured added exhaust burbles included as part of the PPK tune, also included in the PPK was the addition of an extra radiator, higher performance fans on the main radiator and better air flow ducts in attempt to deal with any extra heat caused by the tuning. M3 model The M3 model was powered by the BMW S65 V8 engine and produced in saloon, coupe and convertible body styles. Alpina models The Alpina B3 and D3 models were based on the E90/E91/E92/E93. The B3 was powered by turbocharged 6-cylinder petrol engine and the D3 was powered by a turbocharged 4-cylinder diesel engine. Special Editions 320si To satisfy homologation requirements for the FIA World Touring Car Championship (WTCC), BMW built 2600 units of the 320si. The car featured N45 (N45B20S) engine producing , 24bhp more than the regular 320i. It also featured revised suspension and 20% lower front bumper. 335is The 335is was produced in coupé and convertible models for the North American market. Its position in the model lineup was between the regular 335i and the M3, and approximately 4,500 units were produced. The 335is uses a higher performance version of the N54 engine, which increases boost from . This results in and of torque, plus an overboost function raises torque to for up to 7 seconds. Transmission options were a 7-speed double clutch transmission (DCT) with launch control or a 6-speed manual transmission. The manual transmission has an upgraded clutch compared to the regular 335i. Other changes compared to the 335i include stiffer engine mounts, a higher-flow exhaust system, an upgraded cooling system, a different steering wheel, sport seats and "335is" badging on dash and in the instrument cluster. Exterior differences are larger air openings in the front bumper, a rear bumper that incorporates a diffuser-style piece, black kidney grills, and 18-inch or 19-inch "Style 313" wheels. Model year changes 2008 Facelift (LCI) In September 2008, the facelift (LCI) versions of the saloon and estate were released for the 2009 model year. Compared to typically subtle BMW LCI changes, these changes were relatively extensive. Mechanical changes included an increase in rear track of