OK, this same topic and same parts have been discussed now in multiple threads. I will give you my experience with this company and the parts.
I have ordered essentially the same kit from them but in pieces and skipped a few things I already had or wanted a different brand. The parts are exceptional for the price and the company ships fast, combines shipping and communicates well.
I forgot to ask for oversized pistons on my payment form so I sent back an email saying to change to that. They responded the same day, and shipped the correct pistons the next day. I recieved them and they are Stock OEM toyota parts. I know they are because the box is the exact same as the pistons I ordered from Jay Marks.
I also ordered an oil pump from them. The pump is in fact a Toyota pump since it says "TOYOTA" right in the casting. The waterpump is the exact same casting as the one that came off my 89T...down to the same cast marks. I did not get a gasket set from them and the timing kit was the same price at champion. I only wish these guys sold Stock rods!
I dont know where these guys are getting the parts, and I dont actually care. I got em for a steal and I fully expect them to be as good as this motor was when it came from the factory (granted, Im upgrading the oil system and cooling and headgasket, but my internals will be the same)
I promise when my motor is running I will post up a review of the parts. I have also collected pictures of the parts and shown camparison with the stockers. It will all get posted as one big update to my build thread when Im up and running.