This model was also developed into a more conventional three-box design with a boot (trunk), badged as the Vauxhall Belmont in the United Kingdom, launched at Frankfurt Motor Show in 1985.

A convertible version was also available, for the first time in 1987, built by Bertone of Torino, Italy, bringing it to line with competitors, such as the Ford Escort and Volkswagen Golf.

In the fall of 1986 a new 1,998 cc engine replaced the 1.8 hitherto used on the GSi and Vauxhall Astra GTE in many markets, although the uncatalyzed 1.8 continued to be built for some places until the end of production in 1991.

[6] In 1988, a 16-valve twin-cam version was developed for a high-performance GSi/GTE model (the first application of the 20XE "Red Top" engine), yielding 156 PS (115 kW) in non-catalyzed form, six less horsepower with a catalytic converter fitted.

[7] The Kadett E was a grey import in the United Kingdom, but not popular compared to its badge engineered sister, the Vauxhall Astra Mk II.

[8] There was also a van version with a raised roof, called the Opel Kadett Combo in Europe, and the Bedford Astramax in the United Kingdom.

They featured more aggressive 276-degree camshafts made by Schrick with 2 different settings for timing overlap (110° and 107°), revised intake and exhaust modifications (4-in-1 branch manifold and freeflow exhaust that eliminated the possibility of air conditioning), Irmscher spring kit, modified engine management system by Promotec, a limited-slip differential developed by Andre Verwey, F20 short ratio transmission and special Aluett 7Jx15-inch ET35 alloy wheels, they were nicknamed the "Superboss"[9] and held the world record for the most torque per litre (114 Nm per litre) for a naturally aspirated production car until being beaten by the Ferrari 458 (117 Nm per litre) in 2009.

It is likely that the claimed power was understated,[12] but for tax reasons it was beneficial for Brazilian manufacturers to stay under the 100 horsepower mark at the time.

This was also when the 121 PS (89 kW) 2.0 GSi was added to the lineup, recognizable by a roof-mounted antenna, spoilers, alloys, and clear turn signals in front.

[15] In April 1994, for the 1995 model year, the car was updated with a new dashboard and the power window controls were moved from between the seats to the doors.

[17] The Kadett was manufactured in Brazil until 1998, although the Ipanema ended production earlier as it was replaced by the Corsa estate (introduced in 1997).