For a fun street car i would go an SR, it has more torque and torque = drivability, parts are easy to come by, fits easily, heaps of people have done it so as said above its a slut conversion that is easy 2 get info on.
and before anybody says anything about my KE70 having an SR20 i was very close to putting a 13bt in the rolla, as close as having a 13BT half cut in the driveway.
In a ke70, a rotor has the exhaust on the wrong side which makes plumbing a pain in the arse, is harder to get in stock unmodified form and in good nick (at the time i bought mine only 1 place in sydney would sell rotors with a warranty and they charged $3500 for a series 5 13BT), the gearboxes are huge and you need to do heaps of sump/crossmember mods to make one fit.
Also, the lack of rotary riliability is a crock, build one right and you wont hava any issues. If you have the money a guru roller bearing 2 piece eccentric shaft, nice seals and seperate the rotor face oil supply and the bearing oil supply (ie block off the rotor face supply and run 2 stroke oil in the tank) and have fun :-)