OK what did i brake?

Was playin out at Portland International Raceway on 9-04. At about the 1000 ft mark was going from 3-4 upshift and my car wouldnt go into gear, so i had to coast through 1/4 (12.859 @ 100.08mph). I could not get the shifter to go into any gear, was like the linkage was locking me out. They had to pull me back over to parking lot, sorry all you guys who were waiting on me I had my car trailered home, and went out yesterday morning and was able to get it to go into gear, although it was like shifting an old International Pickup. Is that the clutch heating up and siezing, then relaxing when it cooled down or am in in for bigger problems?
I have stock tranny in my 1999 cobra, about 21 k miles. Whats my best bet now a tremec TKO or 6 speed if i have to replace tranny? What clutch should i get, i do some track days (mild road course) and occasional drag racing so whats a strong all-porpuse unit?

was a pretty hard chunking noise when i first was able to jam it into gear, got better after that, I was thinking clutch too. But how long will t-45 hold up to almost 500 hp block? Whats the best repair/ upgrade now?

Got it into KrazyKoncepts, was a scattered clutch, and some grinding on the flywheel, as well as an almost sheared quadrant cable, looks like i played too rough with my toy, but no fear its gettin better stronger and faster