1st up, read the Hondata website from top to bottom, including the Tech section and the Hondata forum TSX section.
www.hondata.com
If you have an auto trans TSX, just save your money on any ECU mods. It's not worth it.
If you have a 2004-06 manual trans TSX, I would recommend the Little Bo reflash.
Cheaper and easier, no shipping. But he is hard to get a hold of.
I don't recommend the Hondata ECU reflash for any TSX and our 2006 manual trans TSX has it for about 10 years now.
If you have a 2007-08 manual trans, I would recommend the Hondata FlashPro.