An available assistance service tops the short list of New Beetle additions for 2004. All New Beetles have a 4-cyl engine. GL and GLS models have a 115-hp 2.0 liter. GLS 1.8T models have a 150-hp turbo 1.8. These models are available in both hatchback and convertible body styles. Available only as hatchbacks, TDI models have a 100-hp turbodiesel 1.9, and the top-line Turbo S has a 180-hp turbo 1.8, plus unique trim and stiffer suspension. All New Beetles come with manual transmission: a 6 speed for the Turbo S, a 5 speed otherwise. All but the Turbo S are available with automatic transmission: a 6 speed with manual-shift capability for convertibles and TDI models, a conventional 4 speed otherwise. Antilock 4-wheel disc brakes are standard, as are front side airbags that add head protection. Traction/antiskid control is standard on the Turbo S and the GLS 1.8T convertible; it's optional on other New Beetles. Leather upholstery and heated front seats are among available amenities. Among convertibles, the GL has a manual-folding top, the GLS a power top; both include a heated glass rear window and rollover bars that deploy if sensors detect an imminent tip. Newly available for hatchbacks an OnStar assistance system. Other changes for '04 include restyled wheels and available xenon headlights.