I've imported around 15 cars in the last 3 years, mostly Kei trucks. I do business paperwork for a living, so to me it wasn't that big of a deal to follow the rules as laid out by the paperwork. A bit nerve wracking sending money the first time, and definitely some confusion on the paperwork and some moments of "oh shit!" scrambling when I filed something wrong or late. I have no idea what shipping cost are currently, cause they have been skyrocketing, but as of February this year the import cost of a gt4 done privately was around $3500 on top of purchase price - shipping, import fees, boat fees, insurance etc.
I have not bought from goo-net however. Does goo-net do anything to their cars? Like fix or prepare them? If not you might have just as good of luck buying from auctions via a middleman - there's several options at fees of $1000+ over auction price. For me, out of fifteen cars 10 have been good enough, 3 have been excellent, and 2 problematic. There's definitely people in Japan tidying up "barn finds" and putting them out there with minimal effort for foreign buyers, but I just have always assumed buying them at auction was a savings vs buying the same car from an after auction broker.
If you're not good with research and paperwork it might be be easier to go the already imported route. It's the experience you pay for, not just with the import but with local titling and registration as well. BUT you can save a thousand or two if you can figure it out yourself.