If you have O/R X you should be smelling fuel like smell and its normal.Cats eliminate that. Stands the reason why emissions require them in most states. You are putting out a more raw un-filtered smell of fuel.
ON these Coyotes....Yes big time need. The passenger side is the only one concerning enough,but some guys do both which is great too. My first 10,000miles mine would collect alot. Every 700-1000 miles I look in mine and there is always a little. Only got 12,600 on it but seems like the first 8000-10,000 it collected more than now. I don't want no oil on that side of my clinder ya know. If ya running 93-R tune and it's blowing by you probably getting 92 octane and IMO slightly affects performance. I want a clean burn. JMO but many will tell you it's best mod you can do first. Do your motor a favor. For sure watch the oil consumption during break-in. I never seen a motor use the way these do that first 10,000.
If your getting blow by I would def recommend a catch can. They do catch a good amount of oil. And make sure to empty it at every oil change
