John Lapaire made his Theater four π's taller and thinner and several others have as well. To be honest, I never have but I suspect it will sound just fine as long a you keep the physical relationship of the woofer and tweeter the same. Keep them the same distance apart and you'll be OK. I'd also suggest that you might also model the system with Martin King's spreadsheet to make sure standing wave modes don't cause a spike in the midrange.About laying the Theater four π sideways, that will work just fine but I would suggest that you reposition the tweeter so that its horizontal pattern is maintained. I'd probably move it to be above the woofer when placed in this position too.