My 1600 crossflow breathes heavy amd smokes a bit as well, in fact all of the crossflow escies I've had did. Ive never worried too much unless they started banging and rattling as well. They are pretty bullitproof motors even when theyve been played with so I wouldn't worry too much.
On another note if its the car in your sig I nearly started selling body parts when it came on ebay, proper lush!