so you wanna do a rb swap

i found this weblink. that entails on a rough idea on how to do the skyline swap on the z. but i want to know how hard is this swap to pull off. ? i was looking on ebay and a few other sites and i found a few motors for around 1-3k.

JDM RB25DET R33 NISSAN SKYLINE 94-98 Engine Swap:eBay Motors (item 380122054674 end time May-14-09 07:03:09 PDT)
but would a swap like this even be worth it. im also toying with the idea of swaping in a 350 or a l28et. which i know some guy has one for sale for like 800 bucks. thought ideas good website to start with what are some of the shops you all have delt with. when you guys do your swaps ??