I had posted this query in another thread but don't think it was the right place to ask so am re-posting here. I'm considering buying a new MBP13, and was wondering if the non-user replaceable model can run at full performance when the battery is dead if constantly powered up and run as a desktop. Does anyone have any ideas? Is it actually possible for user to replace battery? - ie: Apple don't endorse upgrading HD in Mini but that doesn't stop people! Finally, how easy is it to replace RAM and HD in the new MBPs compared to doing same in a) the Mini and b) the older MBP (or uMB) with user replaceable battery?