like mr2silvertop said, AW11 is a chassis code.
- A indicated the engine family, either a 3A-LU, 4A-GE or 4A-GZE engine.
- W means MR2
- The first 1 means 1st Generation of the MR2
- The second 1 indicates the cars' trim level, in this case it just shows a chassis code. AW15 shows that the car is a supercharged model.
SW20 refers to a second generation MR2, and ZZW30 to a third generation.
Another example; SW22
- S indicated the engine family, either a 3S-GE or 3S-GTE.
- W means MR2
- The first 2 means 2nd Generation of the MR2
- The second 2 indicates the cars' trim level, in this case it shows that the car is a turbocharged model, so it has a 3S-GTE.