Some people collect stamps, some people modify cars. It's a hobby. Maybe it's genetic, my father was a mechanical engineer and I don't remember him every having an unmodified car; I was a shop teacher and I have never had an unmodified vehicle.
The older folks in that thread seem to be in their 30's to 40's which would put in the middle phase of car mods. During the first phase in the teens and 20's, your funding is limited but you still make some fairly radical mods to your daily driver using every dime you can scrape up. During your 30's and 40's, you have other demands for your money, so mods are limited to small appearance and ICE mods. After 50, when you are a little more financially secure, mods get more radical and are mostly done to *project cars*.
this is something i've started to notice about myself and i'm only 23. i am married and own a house though so i guess that is partly to blame. i may eventually buy a car and leave it pretty close to stock but i don't think i'll ever get tired of racing. hopefully my next car will be so good that the only mods i do to it are a set of koni dampers and r-compounds. thats what is so attractive about the SRT-4. all it needs is a little suspension work and some sticky r-comps and i'd be happy. it definitely doesn't need much more power, if any. and now it even comes stock with an LSD.
I'm kinda halfway there. I don't think I'll ever stop modifying cars, or wanting to drive fast cars. I just get tired of doing if EVERY day. That's what my plan has always been with the Focus, I'll modify it so that it's a competition machine I only drive on weekends. It will sit in the garage, nice and clean, and I'll take it out on weekends for cruising, open track, or rallies. It will be thoroughly built now, so that I don't have to dump tons of money into it all the time. Just keep changing the oil, brake pads, etc. It should always be ready to go race at a moment's notice.
But I would like to have something more comfortable to drive every day. Still fun, but more comfortable. 2.3 ZTW comes to mind.
Lot of people were saying things like "It's not a good investement... poor resale... etc." but that's not the point. Cars can be an EXCELLENT investment in fun, if stick to a plan, and don't keep selling your car everytime something new comes along.