They're in this guitar:
Changing pickups isn't really something I'm good at so I was wondering if the ones in this guitar will do for any metalcore or thrash. For those of you that don't know what metalcore is, it includes bands like the old Avenged Sevenfold, Atreyu, All that Remains, Bullet for My Valentine, Killswitch Engage, Shadows Fall, etc... I am playing lead if that makes any differance.
You don't need to be good at changing pickups, theres nothing to do but take out the old ones, unsolder the connections, put new ones in, and resolder.
I am going to buy buying a B-52 A-T 112 60W all tube once I buy the guitar, my current amp sucks extremely badly.
Okay, buy the amp first.
If you like how the guitar plays, go for it.

Agathis isn't really that bad, it's just a cheaper wood for manufacturers to buy. It sounds similar to alder. But cheap guitars built with agathis are often cheaply made and have cheap hardware. The cheap construction and hardware contributes more to poor tone than the alder, but it leaves a lasting bad impression in peoples minds.
You're right. I should probably play a similar guitar in the B-52 before I buy anything. Looks like a trip to GC tomorrow.