The "sirloin" part is extremely deceptive.
Think "round" when considering recipes, not "sirloin". It tends to come out pretty similar to a rump roast.
I agree that oven roasting is your best bet.
Have you bought it yet? I'd pass personally, that's pretty high, especially for a 5-pound chunk. I don't buy beef round or chuck until it gets below $2.99/lb.
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