First things first, what are your plans?
You could go with Nodular Iron (stock)
Cast Steel (better, and would probably be fine in 75% of the street builds)
Forged 4340
The forged will handle 1000HP+, the cast will handle 600 all day long.

The price difference between the forged and the cast steel isn't much, so i'd go with the Forged but for a street car it's not needed. You'll probably split the block before do you anything to a cast steel crank anyway.
As to the kits, I went with a Probe Industries Forged kit, spun it to 7500+ NA a TON of times for the Street Bandit motor making over 600HP. Tore it down and had no problems, only had an issue with a bad bearing after we rebuilt it, components were fine.
Kit was forged pistons with tool steel pins and spirolocks
forged H beam rods (6.250)
Forged Crank

Couple of things:
you piece together a kit and you'll have to pay to get it all balanced, out goes the minimum $ that you just saved if you saved any at all.
You have one neck to wring if there are any issues, vs. going to each manufacturer and playing the finger pointing game.

just my past experiences for whatever they count for.
sorry for the long winded note.