One of the first tuning proposals for the 2011 Smart ForTwo comes from Carlsson who is offering exterior and interior enhancements for both the Coupe and Convertible versions.
At the exterior the Carlsson 2011 Smart ForTwo Coupe and Convertible come fitted with LED daytime running lights at the front, two black radiator grill inserts made from powder-cated stainless steel and new alloy wheels.
Inside the Carlsson 2011 Smart ForTwo Coupe and Convertible received the tuners leather package which combines Napa leather and Alcantara covering areas like the instrument panel, knee area, steering wheel, instrument cluster, air vents, center console, doors and seats.
The Carlsson 2011 Smart ForTwo Coupe and Convertible have also received the high-end ‘Exlusive Edition’ sound system that features a digital two-channel amplifier that outputs 400 Watts RMS, a 16.5 cm loudspeaker and a textile tweeter. 
Pricing details regarding enhancements performance on the Carlsson 2011 Smart ForTwo Coupe and Convertible are available in the official press release below.
Carlsson press release :
    * LED daytime running lights individualise the front
    * Leather packages ensure high-quality interior
    * High-end sound system specially developed for the smart
So much luxury fits into only 2.70 metres. The automobile manufacturer Carlsson transforms the practical smart fortwo Coupé and Convertible into individual, classy cars for the necessities of urban living. LED daytime running lights, exclusive leather packages which start where the factory left off, and an audio system for the finest sound experience make this winning model unique.
At the front, the two black radiator grill inserts of powder-coated stainless steel above and below the number plate provide a note of individuality (from 153 Euro including VAT). In addition, the LED daytime running lights make the Smart stand out from the masses. And here once again Carlsson from Gut Wiesenhof in Germany demonstrates what care they take with their conversions: the LEDs have been approved not only as daytime running lights but also as sidelights. This means they may be used at the same time as dipped headlights and so set themselves apart from the typical upgrade kits. The ready-to-fit set, including the power supply and control unit, the cable harness and the bracket, is provided by Carlsson for only 415 Euro. As usual with products by Carlsson, the bracket requires no painting.
The all-round luxury in the vehicle interior is taken care of by the leather packages from the customizer based in Merzig, Germany. The finest ‘Softwalk’ Nappa leather and Alcantara now envelope the entire instrument panel, the knee area, the steering wheel, the instrument cluster, the radio and air-conditioning console, the air vents, the doors, door pockets and of course both seats, including the quilted lozenge pattern and the embroidered Carlsson logo in the headrests. The complete leather package is available from Carlsson for 4163 Euro.
For a mere 359 Euro more, smart passengers get specially developed sports seats with more pronounced, contoured bolsters on seat and backrest which also provide perfect support when cornering fast.
And for those who wish to enhance their original Smart leather equipment, Carlsson has an appropriate offer on hand. For 2559 Euro the upgrade covers ‘Softwalk’ Nappa leather and Alcantara on the instrument panel, knee area, instrument cluster, radio and air-conditioning console, air vents, doors and door pockets. Furthermore, to suit every interior colour, the automobile manufacturer provides a gear selector in finest leather for 89 Euro in the colour combinations black and silver, black and red or black and beige.
For audiophile pretensions Carlsson has developed the "Exclusive Edition" high-end sound system specially for the Smart. The audio system, which has been adapted to the fortwo’s and the Convertible’s vehicle interior, consists of a digital two-channel power-amp with 400-Watt RMS output, the pre-assembled cable harness for the original Smart radio and sound insulation in the doors. The two, black-leather covered doorboards enclose, behind the loudspeaker grilles with the Carlsson logo on each side, a 16.5-centimetre loudspeaker and a textile tweeter which, connected by a specially adapted crossover network, ensure perfect high-frequency reproduction and full-bodied sound. The audio system for 1295 Euro also includes as a special feature the LED footwell lighting which is activated when the doors open.
With the comprehensive customizing package, the automobile manufacturer Carlsson transforms the small city runabout into a luxurious vehicle for the metropolis.

Source: Carlsson