I was exactly in this situation 3 years ago - Thai or CL9. Preferred CL9 shape just slightly. But when I learned that Thai has K24A4 and CL9 K24A3, my decision became easier. Thai engine has lower compression ratio, lower redline and is rated at 165 hp compared 190 for the CL9. CL9 is also smaller which i actually prefer. Thai has set fixed features whereas CL9 comes in many variants with huge difference in features / options.
Main problem with CL9 is transmission going toast, which is a bit common. Aside from that, personally I went for a low option model - but best to get yourself a full option one. Aside from that, firstly because I was looking for non option model so less items to check, and secondly I back myself for bringing the car up to condition, I didn't look too closely. Others can advise better on more detailed things to check.