BTW, you want the wolff spring kit, trust me.
It dramatically improves DA to the point it's actually useful.
I'm a good DA shooter and LIKE the trigger on my Kel Tec P11, if that's any reference, but the stock DA as it comes on the P64 is good only for 7 yard shooting and I'd miss the paper half the time in DA doing that! Now, after installing the 19 lb trigger, I hit 6" plates at 25 yards in DA easily. Best transformation of a firearm I've ever witnessed just from a spring replacement.
The SA needs no improvement. Has a little creep in it, but not enough that you notice while firing. It breaks at estimate 3 lbs or less, really TOO light for my druthers, but it does make plinking fun. The thing is astoundingly accurate. You'll like it and you'll keep on saving over that Walther every time you buy ammunition.
Bonus, you can actually find it, too.
Oh, yeah, for ammo, Academy regularly stocks Monarch for under 10 bucks a box and usually has it in stock. Try
www.ammunitiontogo.com for ammo in bulk or Silver Bear hollow point for carry.