Beef tri tip can be marinated just like any other piece of meat, and in fact, it's a good way to add flavor.
There are some that believe a tri tip should be seasoned with just a bit of salt and pepper so the flavor of the beef is more prominent. But it's your meat, and you can season it any way you want. It just depends on the final flavor you're wanting.
But don't overcook the tri tip. It's not a brisket, and it's best when cooked to medium rare, or no more than medium.
