i'm looking to buy a pair of 6.5" infinity kappa 3-ways for my brother's '93 integra GS-R, but i want to find out the depth that the panel can accommodate. is there a list or another way to find out whether or not they'd fit?

Crutchfield tells you which speakers fit of the ones they carry. But there are a whole lot they don't carry. www.metraonline.com lists the actual maximum mounting depth.