Here's what I know on this subject.
I just got my machined parts back from PRC and the work is jewelry and top notch. I can't speak for Lahaye, as I've never used him.
I do know that PRC was one of the first companies doing port work for the XR50 here in the US. They aren't the cheapest out there, but in my opinion, are one of the best.
I've been building Honda 50 and 70'cc motors before building motors was cool. I remember when Classic Honda was out of Lyle's Garage and a storage facility. I remember when Powroll was the only game in town, and parts were extremely difficult to come by before websites were popping up all over the place. I remember two bros before they started selling Takegawa parts and only had a big-gun pipe for the Z50!
I've restored a 1967 Honda Z50M, a French Model no less, that took me 2 years to accumulate the parts from all over the world including the Netherlands, Belgium, Japan, France, Australia, and of course the US. For those of you that don't know, the Z50M was launched internationally 1 year before the 1968 Z50K0 was released in the USA.
If I lived in CA, the only person I would take a motor to would be Jeff Tuttobene at minigunz.com. I guarantee he's been building 50cc motors longer than 99% of the mini population, and is one of the nicest guys in the industry. PRC turned my parts around in 10 days, including the time I dropped the box off at FEDEX.
So, for da pimp to waste my time asking me stupid questions via Private Message, I'm entitled to waste his time on subjects that he knows very little about except what others feed him to take his hard-earned cash.
P.S. With my little 108cc Motard, I just topped 70 mph on Sunday on 10 inch street tires, and my total cost to build the motor including all the engine parts was a mere $1200.00. And, I need to regear the bike, as at 70mph, I'm only pushing the bike at 11K rpms.. I'm running a 16/33, and am going to switch it to a 15/33 to get another 1k rpms out of the top end at full bore...
The PRC prepped parts are going into an 88cc motard, and I'll post some dyno graphs when it's all said and done. This motor will have a total build cost of less than $1000 for everything including the clutch, oil pump, cylinder, piston, head, machine work, etc.
Buying off the shelf parts and paying extremely high prices is fun and easy, but to do your homework and build your own combinations is cheaper and more exciting.
I especially like the work KAOS is doing with his bike!