were more lenient to that of the championship rules until 2005, which the same rules apply to this day. D1 Street Legal As the D1GP category was moving away from its grassroots during the earlier days, and budgets and development costs were getting higher, the organisers introduced the D1 Street Legal (D1ストリートリーガル (D1 sutoriito riigaru in katakana), as D1SL) category at the Odaiba round in 2005 for road driven cars which were different from the main category as they are trailer driven between races. Being a budget series, this meant that there is tighter restrictions on how a car can be modified. For example, the car must have a working car stereo system and must have the original engine which it was originally supplied with. Also there is no wide body extension and wings must be within the width of the car. The car must also retain many of its original features, especially dashboard, doors, etc. which sometimes can be replaced/removed/modified in the D1GP category. In all the car has to prove its road-worthiness by its entrant providing a shaken certificate. Initially, the new series was treated to two exhibition rounds in 2005, and was given a full seven round the following year. Although the series is geared towards novice drifters, it also attracts D1GP star drivers including the Suenaga brothers, Masao and Naoto, many of its former D1GP regulars, and fan-favourites like Ken Nomura. In 2006, the organisers started a divisional series called D1SL Divisional Series which does not require a D1 License and is broken up in four regions: north, south, east, and west, with rounds that consist of 3 to 4 events in each region and a point scoring system that is the same as the other series'. The winner of the series at the end is awarded a D1 License. In 2017, the organisers announced the end of the D1 Street Legal series, being replaced by the D1 Lights series from 2018 onwards. Typical D1 Street Legal vehicle regulations Although the items that are prohibited in D1GP also applies in D1SL, additional prohibited items in D1SL cars include: Sequential transmission. Fuel cells. Carbon/beamless/FRP door replacements, must be OEM doors with side impact bars intact if possible. Airjacks. Tubbed fenders/one-off metal body components, must be one that is available to the public. Custom/standalone relay/fuse switchboxes. Acrylic glass/polycarbonate window inserts and replacements, must be OEM glass. complete dash