A "racing clutch" is more likely to kill the T5! What kind of power are you making? I've seen 4cyl t5's live for a while, behind slightly modified v8's. Not saying it's ideal, but it may work ok if you use a stock(ish) clutch. If you're running this on a dragstrip, you'll want to use bias ply slicks. A sticky tire with stiff sidewall will trash a t5, as well. I would suggest a billet steel cluster shaft retainer plate, steel input shaft retainer, and re-shim both shafts to have a very slight preload. About $150 in parts and an afternoon at the work bench can make all the difference in the world.
Now here's another thing to consider. If you have (or plan to have) a lower rear gear, your 4 cyl t5 1st gear may be too low. If you're sticking with stock gear, the 1st gear will be ok, but your rpm's may drop too low between gears. If you switch to a v6/v8 t5, the input shaft won't work. They probably make a compatible pilot bearing. My knowledge is severely lacking on the 4 banger stuff. I'm needing a crash course, though. I just bought an 82 capri roller. I'm going with a 2.3 n/a and t5!