what do you normally do?

When you guys get subs and put them in the trunk do you still have your stock speakers in your car on or hooked up and playing? Do you guys unhook them or do you replace them with better speakers?

replace them...

Did you really just ask if we unhook all the stock speakers when we add subs?

When you guys get subs and put them in the trunk do you still have your stock speakers in your car on or hooked up and playing?

Affirmative.. Yea, I have my Phoenix Gold Titaniums playing the full range... Wow.. Great Highs on those babies :screwy:

the factory midranges cannot keep up with a decent sub system

Well, my subs can handle more highs than yours bmw

Definitely better to replace the stock speakers (and get a separate amp(s) to drive them), but you can probably get by with letting them play in the stock configuration until you actually replace them - that is, if all you're doing is getting a mono amp or something to drive the sub(s) in the trunk.
Good luck!