When a turbo spools is dependant upon more than just the size of the turbo(with the hotside having a greater effect, btw). As it is a load sensitive device, the car's weight and gearing also play a huge part. I can floor my car(not a Honda by any stretch of the imagination, though the turbo principles still apply) rolling in first and still be in vacuum at redline. Yet if I launch it, I'll hit full boost nearly instantly and blow the tires off. Even if I bog it, it spools very quick after falling flat on it's face(I'd tell you how it would do with a proper launch, but with 165 series
rear tires, this is no easy task!). Why is this? Load. You hear about people saying how "my turbo kicks in at 4k, yo". Great, but in what gear? It's not like a cam that "kicks in" at a certain rpm.
And do'nt forget the exhaust! With the header, velocity is key. You want as small and free-flowing a header as possible without choking things up in the upper rpm's. Too big, or small and restrictive, and the velocity suffers. After the turbo, you want as little backpressure as possible! More post turbo backpressure= slower spool, less power.
Now, back to the topic on hand, most Honda engines, if anything, are awesome motors to boost and the fact that there are TONS of very fast turbo Honda street cars proves this. Why is this?
1. The massive amount of tuners that are able to build/tune Honda engines to meet the owners' needs.
2. The massive aftermarket.
3. Reliability of a properly built powerplant.
4. The high VE of the popular Honda engines.
It's not exactly a bad thing to say that a b18c does'nt hit full boost until 4k(and remember that this is'nt a constant, lets say in 3rd wot 0 % grade 70* ambient) because that means that there is 4k in full boost. You do'nt need a lot of power to scoot around town. Yet when you get into it with a proper turbo will provide oodles of power all the way up. A small turbo will be like a semi, but it'll choke on the top end and wo'nt make the power of a properly sized turbo. This is not to say that a small turbo ca'nt make for a fast car or a big turbo for a slow one. To put up with big power, a comprimise has to be made with spool. This is true of all cars and there ar'nt very many ways around it. Wheels can only get so efficient, ball bearing chra's and vatn turbos are pricey, and too small a turbine for the compressor results in surge.
Ok, maybe I rambled a bit. Regardless, Honda engines do just fine with boost if done properly.