I've decided to spice up my Mexican J bass and I need a bit of input on a preamp! I've got my heart set on Bartolini p'ups but I'm unsure on the preamp. The John East is appealing because of the easy install, but a Bart preamp for example would be nearly half the price! What're the main differences between the two? And will I need to route the bass for the Bart pre? Cheers!