I just did the front doors on my 147 GTA. Replaced with a set of Boston PRO60 components that I've had sitting around for a while.
I'm fairly happy with the result, but TBH I didn't think the sound was too bad to start with. The stock tweeters were pretty good, but the Bostons are noticeably better.
Not using an amp.. Just driving directly from my Sony XAV-AX100 head unit.
Also didn't run new wires..
I got the speaker spacers from Dynamic sounds and wrapped them in butyl tape. Also used butyl as a gasket between the speakers and the spacer.
I was a bit concerned about how I was going to attach the tweeters in the stock location, but it ended up being simple. They were exactly the same diameter as the tube that the stock ones screw into, so I just attached by wrapping butyl tape around them.
I got a set of Soundskins speaker rings and used the front rings to seal the space to the door card and the diffuser behind the speaker to reduce standing waves. Maybe not that necessary.. I don't really crank up the volume much.
I didn't do sound deadening either.. maybe I'll save that for a future upgrade.
My main hesitation was that I currently love the sound and feel of the engine in the GTA the way it is. I'm not sure what effect (if any) sound deadening would have on this aspect.
Also, as stupid as it sounds - because the sound deadening is hidden behind the door card - I just find that most sound deadening looks messy and makes it feel like some teenager has been making superfluous changes to the car.
Those speakers you're looking at seem like they'd be a dead simple drop in.
The only thing you need to worry about is removing the door card. The biggest issue there is the screw covers on the door pulls. Hard to remove without damaging them.