Hartge 323i RS & 335i
Hartge offered a choice of 2 E21 models. The 323i RS using the 2.3 litre K-Jet M20 power plant and the 335i using the 3.5 litre L-Jet M30 from the 635CSi.
323i RS: clearly based on the stock 323i, Hartge modified the cylinder head, fitted a faster camshaft and a exhaust manifold and exhaust system with better flow. A trunklid spoiler, decent badging and a leather Hartge steering wheel made the car look sportier. And so did the ASS sports seats in Hartge style cloth. Handling improvements were a 25 mm lowered suspension combined with Bilstein gas pressure shocks, 15” BBS alloys with 205/50 and 225/50 tires. Optional was a set of 3 gauges including oil pressure and oil temperature to be fitted on top of the dash.
Specs: 180 BHP @ 6.200 RPM, 220 NM @ 4.300 RPM. Top speed 215 KMH, acceleration 0-100 KMH 7.5 sec.
335i: this was the big step further: as said before the big 3.5 litre M30 engine and matching gearbox from the 635CSi. The engine was slightly modified as was the suspension to cope with the extra power. The rear subframe was reinforced, a 40% LSD with extra mount was fitted as well as stronger transaxles. The front brakes were uprated using 4 calliper brakes and 271 mm vented discs. Further mods (compared to 323i RS): adjustable front and rear sway bars, front strut tower brace, deep front spoiler (again similar to the BMW Motorsport example), side mirrors sprayed in paint colour. The set of 3 gauges was also standard equipment on the H35 335i.
Specs: 240 BHP @ 5.500 RPM, 320 NM @ 4.000 RPM. Top speed 240 KMH, acceleration 0-100 KMH 6.4 sec.
Source - http://www.bmwe21.net/?page_id=360