Correct me if Im wrong but being you have what might be considered a somewhat descent...not great front end(Mbox) and a fairly cheap mic,I would consider...oops damn you only wanna spend 100-150..you might wanna mess with some plug ins,but when you get serious..think about better a/d d/a converters....apogee, also maybe a universal audio mic pre-amp,or maybe a nice channel strip...neve,ssl, I guess it depends what your expectations,and budget permits,of course you dont have to buy high end to get a great sound,maybe do some research on the signal chain,and how each part effects one another,go to a site where recording gurus are at and listen to there experience with products etc,go to a guitar center and play with everything,with out the knowledge,you may end up wasting alot of money,with more knowledge you probably can get more results and spend less.