opinions on 340 stroker kits

I'm with 360 on most things - except I'll never use a hyper piston in a 4" stroke small block. IMO - the max piston speeds are too high for them - althought he mean (average) piston speed is right on the edge of "ok". So for the extra coin (less than $200 more) you can get a decent forged.
I agree 100% on building for future growth. I'll also add trying to do this on a meager budget means you really need to shop around and know what you're looking to get from the package. So be realistic with yourself.