98 motor in a 99, questions and opinions! please take a look.

Ok so once again heres the deal, I have a 99 mustang v6 auto. Im sick of it and decided to upgrade so i baught a complete motor out of 98 gt, it came with injectors, rails, etc. I am going to be getting a T-45 out of a 01 GT to bolt up to it so heres my questions.

-will this set up work out?

-should i run a 98 gt computer and buy a gage cluster to replace my 99's?

-Is the motor and trans compatiable?

-How hard is it to make a auto car into manual? what does it take?

basicly heres what im shoot for right now... tell me what you think...

buy harness and computer from a 98 gt and install it, buy a 98 transmission harness for the trans, buy a 98 speedo cluster, bolt the engine and trans together, lower it into my car, and pray for the love of good to take it easy on me ....what you all think?

thanx,
ryan