So my ecu is: 8N0906018T
I want to flash it with a GIAC Tune that came from ECU #: 8N0906018AT

Both ECU's are from the same year make and model. The only difference I might see is the AT is an Auto and my T is a 6 speed. When I found both ECU numbers referred to, T showed 6 Speed. AT didn't show anything.
If it's not compatible, is there a way to make it work?

Not quite. I want to compare the changes from a GIAC tune to a stock ECU and sort of reverse engineer what they did and try and understand why. I'm very UNSKILLED at reading ECU code... BUT, if the tune isn't compatible and not the same, then trying to understand a difference because it's just not for my car would throw me off. I have been tuning DSM's for years but it was with a SAFC and MAFT, plus a small amount of DSMLink. A smidge different i'd say. Plus, i'd like to make changes in the future. The more I know the less i'll need to post here with amateur questions. Search first, question second.
And to answer your question, no I dont need help with the eeprom reader. I need help understanding if my ECU is compatible with the AT ecu so I don't have to use boot mode... I need to figure out what makes two ecu's different other than their part numbers.

Before you assume some other "newb" wants to steal a tune, you should try and get a decent idea of how badly they want to learn.

Also, don't forget to use proper capitalization.

No one can help me here?!?!