Trex abilities

Forgot to mention, T-Rex killed prey by crushing its bones. A Spino's teeth probably wouldn't be able to handle the force of the bite combined with the thickness of the bones of the Rex's prey. 

Well you dont exactly know that, i think that if spinosaurus had the biting strength of Trex, it cound do about the same. A lot of the damage a Trex inflicted was bite stregth. Spinosaurus had a pretty good bite force, i personally think it could have gone up to a good 5000 lbs, give or take.

Spinosaurus' teeth were built much like those of modern crocodiles; they were conical, unserrated, and pointed. They were designed for puncturing and gripping, nothing more; they were designed for piscivory. Unlike the teeth of animals like tyrannosaurus or deinosuchus, spinosaurus' teeth were designed for simple deep penetration alone and were generally quite slender and sharp; unlike the former creatures, its teeth were structured to pierce efficiently and were not as much reliant on bite force to do surplus damage.

It should be noted that this anatomy does in fact seem to be disadvantageous for crushing as MrHappy said, as they would be particularly ineffective at it and would likely be damaged with such strong perpendicular force. Their morphology indicates that they were structured best to pierce quite deeply without heavy reliance on the same kind of bite force as in tyrannosaurus, as they were rather elongate and were quite sharp at the point but were yet unserrated. In other words, they were well adapted for impaling and resisting lateral stress in fishing, not such powerful biting.

so we can all agree on something? good....good...