Manifold sizing question

[Gravy]

Ok, i've been looking around for some time, and found some answers to most of the odd questions i've had for a while, but there's one i looked for a little bit, and found mixed results for.

Car:
14b, stock almost everything but FMIC and exhaust were changed out

Problem was i had a stock 1g manifold and a tubular manifold for the GSX a while back. The stock 1g was... well you know how great those all are. The tubular had larger runners and looked like it would hold much more exhaust gas.

The difference i noticed with the two of them, is the stock manifold seemed to help out spool a lot, turbo spooled up quicker, didn't hit full boost as hard, but almost felt like it was dying off in the higher RPM range close to red line.

The other one had larger runners, it seemed to up the full boost point by about 4-500 rpm's and when it boosted it was more of a kick in the pants, held boost well all the way up to red line. Now to me this made sense to me from what i've read in the past but i want to get my facts right before i go assuming things on my Stealth in the future.

Did the smaller manifold give the gas less space for the exhaust to build in, and move the turbine wheel quicker giving the gas less space to expand into and releasing most of the energy in the exhaust housing? And if so, choke some in the higher rpm range due to the volume of air going though? Porting the stock 1g manifold only helped right before red line, other then that it was the same in every other way really.

And did the larger one give the exhaust more room to build up in, like a wave almost, to come in on the turbine wheel in higher volume causing a slower spool due to extra space needed to fill the pipes, and more of a volume going though to give it that extra "Kick" so to say?

I know most of this isn't very technical, and it's what i've kinda picked up from a few years of shifting through other people's posts, but on 5 hours of sleep and at almost 2 a.m. in the morning, i'm trying to get my thoughts down before sleep to see if i'm still on track, or if it's time to hit the books again. From what i remember, hot gas stores most of it's energy and releases it upon expanding, which it does in the turbine housing. I'll go more into where i'm going on this if people are confused.

Thanks in advance for reading my long, and probably hard to understand post, and thanks for any answers, constructive or otherwise.