If you use the same shaft, and they all use the same shaft, you won't find a difference in the playability. The only difference in the all the 1k series up to present 5k is the design. If you use a P2 design the playabilty is the same but you might feel a different hit because the butt is made differently. I used to hit with a 3k series . Now I use a scruggs with a 314 shaft. I have a 4k7 for sale. Very Fancy. Lots of ivory and mother of pearl. Mint Condition. Listed for $1145. I bought it from Predator a valley forge 3 years ago. I payed about $950, can't remeber exactly. I have the receipt somewhere. I willing to part with for $850 plus shipping.