There were some reg edits that I did on my TP2 that deleted the counting of characters in texts which seemed to cause a great increase in speed but I haven't got them to work on the HD2. Even after deleting the code from the htm files the phone still continued to count characters. The current options would be to switch back to the 2.10 or 2.11 roms like Nibbley15 suggested or give a custom rom a try as they are usually optimized in the performance aspect so the delay is reduced the best it will be.