Well, after installed the bov, i just run at idle, rev to about 2 ~ 2.5k max so hopefully it not damage anything.
As for the coolant, I did a check today before and after driving to work, seems like it normal now, stay at the same line I topped up last night. No sign of coolant near radiator cap or anywhere in the engine bay.
Also did a few checks for head gasket, oil color normal, no bubble in radiator while the engine is running at warm, she runs fine, no overheat and accelerator still strong. no sign of exhaust leaking this morning so hopefully the head gasket is still good but will have my eyes to check if anything wrong and will bring her to my mechanic.
For the BOV tune, did some research a while ago and they told that it can be tune to fool the engine that the air is not recirculate back, but maybe BOV sound is not worth to all the mess. Lesson learned, will stay away from the BOV, maybe get the 50/50 valve if I'm bored
Anyway, thanks guys for all your inputs