Hi there 8)
the soapbars won't fit into the Jagmaster cavity. if you think you would benefit from an Epi/ Gibson type tone, the best thing to do now is to get Gibson humbuckers which would cost you quite a bit.
the next best alternative is to get other brand replacement pickups, Dimarzio & Seymour Duncan among others, which would be >$100 ea.
PS: which amp are you using?