t5s are tough gearboxes, but are brittle no matter how built they are. I have a 2.95 Z spec gear set in my car. yes it alot stronger than a stock t5 but its not like i can bang gears all over, it will still bite you in the ass if you abuse it.
A t5 is strong no doubt and is a killer 5 speed tranny for what our cars are, cheap and are fairly durable. The quality of the t5 isnt the problem, its how you drive it. If you drive NORMAL lol and make the occasional track trip, and maybe a little goosing and fun around town. It should last a while. If you go around speed shifting and dumping the clutch and hot rodding alot, it will wear faster.