Yea the speakers basically rust out and stop working. Good thing they're super cheap on ebay.
Also, think super hard about NOT doing the IPS mod. While it does improve playability as a mobile, it ruins the classic look/ nostalgia, using an over head lamp, hunched over, your back hurts but you can't stop playing because you've only got 8 minutes before bed time.
The only mods that're sort of necessary are repair components, like if you've got worn out silicone, or scratched screen cover. The glass ones are quite nice.
I'm hesitating whether I should get the Lithium rechargable batteries, they're lighter and have much more stable voltage for sdcard Flash carts which consume more power.
What's cool is you can have the entire library of gbcolor and gb on the same flash cart.
Make sure to get a reasonably fast sd card from reputable dealer, lots of fake out there.