I purchased one over a year and a half ago for $50 off of Craigslist, liked it so much a purchased a second one for $70 from CL a couple of weeks later to run stereo delay in my bedroom. I love em! I havent changed the batteries in either since the day I bought em.
I like what you did to yours, as the stock speaker is my only complaint. The more dirt and/or volume I add the fart-ier the speaker gets. The second MC I bought had a farty speaker that was so bad I called Boss/Rolland for a replacement $20.
Very envious of your new cab and speaker mod!