Download times are effected by your modem, ISP, and how many are downloading from the same server at the same time, which would explain the slow times right now, as I suspect a lot of US and Japan customers are also downloading GT:HD 2.0 from the Euro server(s).
Under normal circumstances, if you are using a cable modem and getting download speeds from your ISP of about 8 Mb/s, then it will only take one second to download each megabyte. GT:HD is 690 MB, so it should normally take just over ten minutes do download. As it took me much longer, clearly the servers are working overtime right now.
A couple days ago though, I was downloading wirelessly to my PS3 the trailers off the UK site in about two minutes each, and they are a little more than 100 GB in length.
One way to avoid download traffic jams is to avoid peak usage times, although with background downloading and the ability to queue downloads, even with congested load times, its probably not going to be a big deal for most people.
BTW: If anyone is interested in calculating how long it might take to download a file from a PS Store
(under normal conditions), you can test your current transfer speeds by using
www.speedtest.net.
SpeedTest will give your current download times in kb/s
(kilobits per second). The files from Sony are in MB
(megabytes), so to convert them to kilo bytes simply multiply them by 8,000.
(Or conversely, you can convert the download time to MB, by dividing it by 8,000.)
So for example a 100 MB file is 800,000 kb. If you have a transfer time of 8,000 kb/s and there are no log jams from the Sony servers, then it should only take less than two minutes to download.
To see how your download times compare with others, GTP has a thread dedicated to just that: