I'm interested to know what the goal is that you're trying to achieve.

A standard road triple is only 52/39/30, newer ones 50/39/30. We're talking a only couple of teeth. Same on the rear where 12-27 is pretty much standard.

Having once owned a Giant hybrid similar as yours, I can say from experience, higher gears won't make that bike faster. Even work on the engine will have only a marginal impact.

However, one thing that made riding my Giant much more pleasant was that I switched from a wide-range cassette to a close-ratio one. At my typical speeds, I was forever hunting between one gear and the next, with one being too easy and the next being too hard. I found I was using only five of the eight on the back, so I got a cassette whose range was the same as those five I was using, but gave me eight choices in that same range.

I gave up the two lowest gears, but I didn't climb trees with that bike anyway. I also gave up the very top gear, but I'm not a Tour de France rider. I had to granny down a bit more often, but that's what the 28 ring is there for. At cruising speeds, however, the smaller jumps between the gears made things much more pleasant, as minor changes in grade or winds could be compensated for with correspondingly minor changes in gearing.

Now, if you're looking for snappy acceleration, and a drivetrain that moves a bike with alacrity and verve, the save your money for a road bike. After the first 100 yards on my first road bike, (second-hand, seven years old) my entire being just said, "Whoa!" When I pushed the pedals, Things Happened. And quickly.

I never went back. I own four of the blasted things now. And I have close-ratio cassettes on every one.