after I replace my exhaust system there's a smoke coming out in the mufflers, is this normal? my friends said that I need to tune up the vehicle is this true?

 

There was smoke coming out of them when you had the stock exhaust on. The X is running very rich and you just noticed it now because you put on a exhaust.

Read this thread.
https://www.evolutionm.net/forums/sh...d.php?t=337113

 

I think the smoke you're talking about is from the oils on or in the exhaust. Every aftermarket exhaust I've put on has smoked and smelled bad for the first few drives but it goes away. Give it a few more days.

 

Black - fuel, cheap to fix
White - coolant moisture, only at start no problem, running a head gasket fix
Blue - time to see a mechanic, take out your wallet and sit and hope its just valves.

 

Probably just smoke from the oils in the exhaust system. Normal.