Interesting video, thanks for sharing.
It's really easy to hit that number modding. Most people just aren't honest with themselves about what they spend but even the little things add up over time. $100 here, $50 there....next thing you know, its a grand for little stupid things.
I'm still collecting parts for my IS38 build and am at over $5K for everything already yet STILL haven't picked up the IC, protune, mounts, sways, springs/shocks, wheels/tires, and new clutch. That's with getting alot of the more expensive parts (AP, IS38, DP, etc) used at a significant discount and others on sale. I'll be at around $10K when all is set and done not including labor but I knew what I was getting into.
Sure, you can skip out on the cosmetic stuff and save a few thousand but its still pricey when you go down the rabbit hole.