i'd love to see an itemized receipt on that.
i just built out a quick and dirty summit cart for a stock rebuild and it was damn near 2K, and i'm sure i forgot some things and stuffs. and that's before machine work on the block and whatever the heads need.
while i don't doubt you could do it for 4K, i think that would be the exception not the norm. the last few i've done have been in the 5+ range and weren't anything special.