Ok.. just got done driving the car for more than half an hour. I made a new friend and it's the Rev Limiter
. I took the car to 7000+ RPM few times, quick downshift 5-4-3, thrashed it around and EVERYTHING is FINE! It's running perfectly.
I have no clue why this happened. Looks like few others has encountered the same problem. For some, it's solved by shutting the car off and restarting. For me, it was putting the car in reverse (which makes me lean more convinced that my issue was a gear/clutch issue).
Good thing is car is running 100% with no issues!