OK I just switched to Mobil 1 synthetic oil yesterday. My car is a 2000 Civic Si and has 17000 miles and the following mods: AEM CAI DC 4-1 header axle-back exhaust. Well as soon as I got my car back and i started driving it within 5 mins. i noticed a bad smell and some smoke coming from under the hood ( just a tiny amount). Well i worried but after another 2 mins. it had stopped so i attributed it to some oily hand marks on the engine burning off. It hasnt done this since. Since last night its driving really sluggish like I have a lot of weight in the trunk. I opened the hood today and the same strange odor was back something like burnt oil but not exactly. I also checked the oil level and it is fine but seems thin--Could that be because its new oil or synthetic or what? Anyway-what could the cause of these problems be? I havent even really vtecd it since i got it changed but i did run it at the track the night before it was changed. Anyway please somebody help me out! I hope i dont have fried piston rings but im sure there would be other noticable warning signs. Thanks in advance.