The lead designers were Paul Bracq and Béla Barényi, who created its patented,[2] slightly concave hardtop, which inspired the "Pagoda" nickname.

The comparatively short and wide chassis, combined with an excellent suspension, powerful brakes and radial tires gave the W 113 superb handling for its time.

[citation needed] The styling of the front, with its characteristic upright Bosch "fishbowl" headlights and simple chrome grille, dominated by the large three-pointed star in the nose panel, paid homage to the 300 SL roadster.

Thus, Mercedes-Benz started evolving the 190 SL on a new platform, model code W127, with a fuel-injected 2.2 liter M127 straight-six engine, internally denoted as 220SL.

Encouraged by positive test results, Nallinger proposed that the 220SL be placed in the Mercedes-Benz program, with production commencing in July 1957.

However, while technical difficulties kept postponing the production start of the W127, the emerging new S-Class W 112 platform introduced novel body manufacturing technology altogether.

So in 1960, Nallinger eventually proposed to develop a completely new 220SL design, based on the "fintail" W 111 sedan platform with its chassis shortened by 30 cm (11.8 in), and technology from the W 112.

This led to the W 113 platform, with an improved fuel-injected 2.3 liter M127 inline-six engine and the distinctive "pagoda" hardtop roof, designated as 230 SL.

It inherited a rigid passenger cell and designated crumple zones with impact-absorbing front and rear sections built into the vehicle structure from the W 111 it is based on.

Mercedes-Benz made a number of modifications to boost its power, including increasing displacement from 2,197 cc (2.2 L), and using a completely new cylinder head with a higher compression ratio (9.3 vs. 8.7), enlarged valves and a modified camshaft.

The 250 SL retained the stiffer suspension and sportier feel of the early SLs, but provided improved agility with a new engine and rear disc brakes.

US models acquired side reflectors on the fenders, Kangol three-point seat belts, an illuminated automatic gearbox shift quadrant, and emission control equipment.

Over the years, the W 113 evolved from a sports car into a comfortable grand tourer, and US models were by then usually equipped with the 4-speed automatic transmission and air conditioning.

[13] Other differences of the North American models include imperial gauges, chrome bumper guards, side reflectors (illuminated from 1970), lower rear-axle ratios for faster acceleration yet reduced top speeds, and no "single-side" parking lights.

[citation needed] European cars were popular US gray-market imports: those vehicles were brought to the US some years after their original delivery in Europe.

Early European imports had aftermarket hazard lights and Kangol seat belts fitted, US safety requirements that were adopted in Europe only in later production years.

[citation needed] The result was appealing but not convincing enough to go into production and remained a one-off that was subsequently acquired by German press baron Axel Springer.

[9] In 1966, the Turin coachbuilder Pietro Frua, a prominent car designer in Italy in the 1960s, presented a coach built 230 SLX Shooting Brake version of the 230 SL.

On 14 September 1963, Dutch Grand Prix racer Carel Godin de Beaufort took second place in class in the Vaals hill climb in a stock 230SL.

Due to considerable mechanical bad luck, Eugen Böhringer finished only third this time, after Rauno Aaltonen on Austin-Healey 3000 and Erik Carlsson on Saab.