stroking is ok on these motors, but really on worth it on the 2v. the 2v's make a lot of torque as it is. these cars are sohc motors, gt's havent had pushrod motors since 95. the big bore kits go up to a 302 on stock stroke and 324 with a stroker kit on top of that. the 98 motor is a npi motor sotck, and 99+ recieved the pi set up. the npi motors pick up a lot of power with pi parts, and a full swap can gain a lot over the npi. as for the motor swap, it just depends on what all you want done. you will have to change the k-member, trans, driveshaft, etc, but is easily possible.