Have a seat and get a cup of coffee, this is one of my epic posts:
It all depends upon what kind of power you want out of either engine, though my comments come from a K24 background.
Stock: I completely agree that the K24 is the right choice
200 hp normally-aspirated (NA): Sure, no problem, $$$-$$$$
250hp NA: Needs internal mods like valve springs and cams, $,$$$. Going to be loud due to the required low-restriction exhaust and high rpm.
300hp NA: About the realistic maximum, $$,$$$, and very very loud due to high rpm and high compression. Will need race gas/E85. Total rebuild with better parts. Has to rev to about 10K to reach that power.
Turbo: No point until you get above maybe 250 hp.
300-350: "Some say" you just add a turbo and go, and that it'll be dead reliable. What's always left out is a detailed explanation of exactly how it's used. Street, probably fine. Drag strip, who knows. Track days, hard to say, depends a lot on cooling.
400-500: "Some say" same as above, just crank up the boost. There are urban legends of people making a lot of power on a stock block, but again, no other data than it did it, but no word on for how long and under what circumstances. At this point it's wise to replace everything with better parts and improve the cooling system in a big way.
Above that: a full build isn't an option. If you have a shop do the work, it'll be $$,$$$
If you're entertaining keeping the OEM transaxle, it's an awesome transmission as-designed, but add power and its reliability takes a nose dive. The good news is that there are options out there, but figure mid $$$$
My story:
In short (hah!) I built a turbo K24 capable of "800hp" but kept the boost low so it never ran more than maybe 400 hp. Additionally, as-built, the rev limit was 9300 rpm, so I shifted at 8000. At trackdays it was run on E85 for insurance, and it was perfectly fine until it wasn't, with a connection rod exited stage left. No one had a good theory about what happened, as due to the damage, it was near impossible to tell what failed first. The bearings were in perfect condition, so no oil issues (was dry-sumped). Half the experts said that the pistons looked like they'd been hot. The other experts said that wasn't the problem. The only possible hint was found a year later when the new engine was being tuned, and the tuner asked why ignition timing was so retarded - and locked. I had no idea, and whether that had something to do with the failure, I don't know.
BUT, I did catch up to the Porsche GT3 on track... priceless, until I coasted to the side of the track and he lapped me over and over... I'm sorry, what was this thread about? Oh, yeah, my point is that if you turbo an engine, it needs to be built really well, with no shortcuts, and that costs money.
My incident track video The funny thing is it was such a subtle failure that I thought that one spark plug had failed. There were no flames, no "kaboom", no locking up. The engine kept running, seemingly fine. It wasn't until I slowed I could hear something and there was a wisp of smoke. Sigh.