The Dodge Stealth and Mitsubishi 3000GT are what would be consider "twinned vehicles." Manufacturers do this in order to expand their reach in various market segments (e.g. domestic/import) and to avoid the high costs of engineering completely new vehicles.
Mechanically, the Dodge Stealth and Mitsubishi 3000GT are exactly the same. At the time these cars were sold in the United States (1991-1996), Dodge and Mitsubishi had a working relationship that allowed Dodge to sell a rebranded version of the Mitsubishi 3000GT with slightly altered body panels. After Dodge discontinued the Stealth in 1996, Mitsubishi continued with the 3000GT in the United States until 1999.
So, while the Mitsubishi 3000GT models included the Base, SL and VR-4, the Dodge Stealth equivalent was the Base, ES, RT and RT/TT. The Dodge Stealth RT/TT is the turbo version of the Stealth, which is mechanically the same as the Mitsubishi 3000GT VR-4. Same engine, same drivetrain, same capability, same speed.
The Mitsubishi 3000GT SL has a Square Front where the Dodge Stealth ES has a slightly pointed square front and slightly lower back the car also sits lower to the ground which is great for car detailing. Other than that it's pretty much the exact same vehicle. Dodge had a Crysler Plant in Nagoya Japan & Mitsubishi had a Plant In Nagoya so they both partnered up with each other in 1990. One can diffently be fooled unless you know what to look for.
The Mitsubishi at fist was only relased in Japan. Even though a few Japanese imports like the 1985 Toyota Supera & Nissan 240zx where around in the mid 80's it wasnt until 1990 that Japanese Imports increasingly popular in the United States Of America. So dodge unveiled the Stealth to help Mitsubishi become more popular in the United States Of America this also helped Mitsubishi bring there cars over to the United States Of America.
The Stealth is a rebadged Mitsubishi 3000GT (GTO in Japan) so it is more like a captive import. The base Stealth and R/T models have front wheel drive (the base has a 160hp engine while the R/T has a 220hp dohc engine). The one with all wheel drive is the Stealth R/T Twin Turbo with the 296hp dohc engine. The R/T Twin Turbo is the equivalent of the 3000GT VR-4.