Go to
www.240sx.org and then to Bulletin Boards. do a search about the RB25DET in a S14. They post quite often about it and everyone on there says it is a good swap. It even fits in without major mods only the crossmember(according to people on there that have done it). It would also be an I6 and not a I4. It can hold 500+HP on stock internals, whereas the SR won't even come close. Go to
www.afterdarktuning.com and see their prices on the complete install. Ask them questions about it. They are very nice and get back to you most of the time in the same day. Maybe I'm wrong, but according to people that have done the swap and use their cars as a daily driver say it's a good swap.