All of those letters and numbers together make up the Mitsubishi model number.
The model numbers that are a direct fit on an Eclipse are...
TD05H-14B-6CM2
TD05H-16G-7CM2
The model numbers that are a direct fit on Starion is...
TD05-12A-8CM2
TD05H-14G-8CM2
The TDnn and nCM2 pieces combined together identify the size of the exhaust (aka turbine) housing.
The TDnn and TDnnH pieces identify the size of the exhaust (aka turbine) wheel.
The -12A, -14B, -16G, -17C, and etc. identify the size of the compressor wheel.