right ive got the box and diff from a UK car, im fitting it into a STI V3 and been told something about the starter motor will be a issue

what is it i need to do before i start stripping the box out to find the issue and also what else should i worry about too before i start doing the job as ive got a weekend ONLY to start and finish it which means no time to buy suprises

Please help me !!!

photos of work to do would be a bonus,, though never gonna happen pmsl

 

*cough*

anyone here that can help me ?