I've had good success with replacing the K1 spring with the kit from the dealer, like $13 a year ago. I also tried using a K1 spring kit to replace the K2 in my it helped a little but not a whole lot. I think I'd go for the Superior Shift Kit. I think you get more option for adjustment from those kits.
Here is my thread about my 2-3 and 3-4 flare.

3-4 flaring shift.

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