After researching several sites and forums, i've decided to get Joe-Z full catback exhaust.
At idle it's pretty quite, yet once you step on the gas, sounds like a beast. I do get pretty decent cabin drone towards the trunk area which it's acceptable for me but it might be uncomfortable for other passengers. Since lexus is pretty good for insulation it does not bother listening to music but if you are into easy listening, jazz or classical then this might not be suitable for you.
Some of you might not like the sound but i get complements left and right asking what kinda exhaust, so i'm happy at this point.
I will be driving long distance this weekend and see how it goes.

 

Congratulations on the exhaust. You can't go wrong with Joe Z

 

thank you~