Hi, I currently have a 2yr old 27" non retina iMac i5 with 32gig ram and 3TB fusion drive. I think it cost around £1700 with the fusion drive eating up a lot of the cost. As I couldn't upgrade it myself, I thought might as well future proof it. The setup is pretty overkill for my needs which is mainly browsing, photos, sabz/plex, and maybe one game a year. I do plan on getting xcom 2 when it's out but it's not the end of the world if I can't play games. I'm considering replacing this sometime before my applecare runs out, and a good candidate would be the retina 27". With a decent size fusion drive, this would again be ballpark £1700. Which is a lot. So I was thinking, could I potentially replace this with a 13" mbp connected to a 4k screen? I visit Hong Kong every year so the middle 13" mbp costs less than £1000 there. I think a 27" screen is around £400 and that won't need replacing very often. At under £1000 I don't really mind having to replace the mbp every couple of years if required. My minimum reqs are a 27" screen, preferably 4k, 256gb SSD or fusion drive. I haven't had a mb since the white plastic ones ages ago so I don't really have much recent experience with them. So my questions are: 1) I leave my imac on all day for downloads and cctv, can I do the same with the mbp? 2) Can I leave the lid closed? Presumably the mbp screen will be off but the monitor will stay on? 3) What's the wear and tear on the components like if I leave on all day? I don't plan on taking it out the house at all. 4) Can you take the battery out and run on AC? I don't want to kill the battery by leaving it charging all day every day. 5) Will the 13" drive a 27" 4k without any slowdown? 6) Is the ram user upgradable? 7) Assuming I max out the ram, what's the real world performance like? I don't want it to be noticeably slower by much. 8) Any other advice/suggestions? Is what I'm considering crazy? thanks!