The Rb26 is a heavier motor, but is capable of making a lot of power as well. But you need to consider the cost factor and the fact parts are much harder to come by. Also, you need to think about tuning. In the terms of the whole country, there are many more sr powered vehicles vs rb powered ones. Tuners rarely come by rb motor cars and are much more experienced in tuning for the sr20. If you are looking to make under 450hp, I think the sr20 is the more efficient route. But if you have the money, and want to be able to pop your hood and tell people you have a skyline power plant, go for it!