I don't know that you'll find a non-Chinese kit, but your local Sears store may have a more professional version for about the same price as the Harbor Freight kit. I picked mine up at Sears and it happened to be just like the version my dad had before he retired, except mine said "Craftsman" and his was some other professional brand.
The powertrain diagnostic codes are most typical, and often the only code types that the standard consumer-grade scan tools will access. But, there are other code families....
The P1744 is a transmission diagnostic code meaning excessive slip was detected during full Torque Converter Clutch (TCC) engagement. When's the last time the transmission fluid and filter was changed out?
The P0340 indicates that Self-Test has detected a Camshaft Position (CMP) Sensor circuit failure. This is likely due to a bad CMP and/or CMP synchronizer. This is a pretty common issue on this engine and there are a few threads that will help you understand what is involved in changing it out. This could very likely cause the poor idle and lack of power.
The P0430 indicates that bank 2 catalyst system efficiency is below the acceptable threshold. I'd fix the CMP issue before getting too excited about this one.
The P1131 indicates that bank 2 catalyst system efficiency is below the acceptable threshold. This could be related to the P0430 and again I'd fix the CMP issue first. If after fixing the CMP sensor and synchronizer you still have a rough idle, then start searching for the vacuum leak which is then probably triggering this and the P0430 codes.
Certainly a typical tune up would not be a bad idea if you are planning to keep this car awhile as well.
-Rod