Do a search or you will get grilled by TR's finest. But Im am not one to grill so basically the RB makes the 240sx nose heavy to start...it adds what some say up to 200+lbs in the front from the motor and tranny being so beefy.

Second, parts are very very hard to come by...for example, its been said that it can take up to 3 months to get a factory waterpump, gasket, etc as most of the parts have to be ordered from Japan.

3rd, the parts are typically 3 times as much as the say, SR parts because of availablity, demand, etc. It can handle a good amount of hp and tq, but so can the SR for example. Taylor at XAT has done 2 I believe and says its hard to drive and if drifting is your cup of tea, forget about it. I had the same questions a while back and we had a good debate on it...do a search and look it up.

XAT will do the swap for you, but its going to cost some cheese. Also, from what I've heard, its somewhat hard to get tuned around these parts because most shops around here dont deal with RB's. So thats another issue altogether.

I think its still a good idea and I plan to do it, but Im going to do my first 240 with a SR then my second S13 or S14 with a RB as a project possibly.

Also, I believe the pistons in the RB25 can handle a good amount of power, but I've read a few places that they arent too good with high hp...but Im not 100% sure.

For the money you spend on a RB, its said that instead of having 4 times as much going wrong, you have 6, and for the money you put into a RB, putting the same amount of money into a SR will give you far better results.

Good luck.