Broiled Sirloin Steaks with Lime and Garlic

Given my frugal nature, I've never purchased sirloin steaks before. I needn't have worried that our family would miss out, though. My mother-in-law is beyond generous-- she pretty much spoils us rotton, so much so that I'm helpless about how to adequately thank her. Their last trip up, she and Dude filled our freezer full of different kinds and cuts of meat, and included in these were some sirloin steaks. Becky found this recipe for me to try out, so I tested it on Mother's Day and found it good enough to post. I'm a sucker for garlic in its many uses, but its taste paired with hints of lime is a new (and wonderful!) one for me.

2 tablespoons lime juice
1 tsp onion powder
1 tsp. garlic powder
1/4 tsp. ground mustard
1/4 tsp. dried oregano
1/4 tsp dried thyme

4 boneless beef sirloin steaks, about 5 oz. each (Ours were bone-in and larger)
1 cup sliced fresh mushrooms

In a small bowl, combine the first six ingredients; rub over both sides of steaks. Broil 4 in from the heat for seven minutes. Turn steaks; top with mushrooms. Broil 7-8 minutes longer or until meat reaches desired doneness (for medium rare, meat thermometer should read 145; medium, 160; well-done, 170) and mushrooms are tender. Yield: 4 servings

I made a few changes:
I doubled the lime mixture and marinated the meat in it for at least half an hour.
I added some minced garlic in with the lime mixture, too.
Oh, yeah...I also scorched half of them when Susannah fell down the stairs, so they were dry on the outside and raw on the inside. (The first batch was excellent, though!)

If you're an expert meat broiler or griller (which I'm not), please leave some tips for me in the comments. I'll take any help you're willing to give.