Sorry, probably nothing you can do about this, since most throttling solutions use packet inspection. Changing the ports doesn't help.
The only thing you can try is to use some "less well known" ports like 1677 or the MS-SQL one (kinda forget which one that is, 4523 maybe?) But most likely changing ISP is your only option here.
What you can try is setting your new connections / 5 second to a very low value, like 1-2, and your max connections to <100. This might keep the throttling to a minimun, but only if your ISP uses TCP-thread dropping software which is triggered by many (incoming) connections. Obviously your downloads will also be impeded by this.
