I'm looking at this car to buy and its a 94' teggy and the swapped 76,000 mile motor in it is a B18A...how different is this from a B18B? Also its auto and I HAVE to have manual

so I was wondering how difficult auto to manual tranny swaps are in these cars and on this motor, as well as how much say a gsr tranny will run me. Thanks for any help and plz be as detailed as you can
Thnx- HUFF
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Engaging in Full Internal and Turbo Build on my '94 GSR Teg for my high school senior masterwork project

...Daily driver is '07 Subaru Impreza 2.5i...I AM a hybrid of BOXER RUMBLE and VTEC SCREAM