As BG players we all love subquests and we all love to scramble around for experience, exp. and more exp.
Since exp. is split up between group members, I want Imoen back in my group asap so I can properly develop her mage skills. She's by far my prefered mage in the game, and I really want her back again.
But if I bash right through and save her, I will already be in Chap 4 right? Am I able to return and do all the quests around the city after that or is this impractical?
I know that most quests are designed to be completed in chapters 2 and 3, so what can people suggest? What happens after saving Imoen? Is it just one big dungeon crawl to find Irenicus or is there quest/exp. time?

I'm not quite sure about that but maybe, to say the truth i think you can.

all the sidequests you can do in chapter 2 or 3, you can also do in chapter 6 so don´t worry. if you intend to get imoen back, i´d recommend getting your stronghold, then heading straight to spellhold.

Thanks, will do. Although Jan is also a pretty good theif to have around seein as he's so damn amusing and all, so maybe I'll just have him hang around in Imoen's spot (cos Nalias off being kidnapped by her fiance and right now I'm not screwed to rescue her) and do a bit more quest solving.

I make sure I have at least five party members who have over a million experience points each and are equipped with the best possible things before I go off to Spellhold. I should actually wait longer before getting Imoen, but sometimes my motivation lessens if I hang around Athkatla too long, I feel like I'm not really getting on with the main story.