I imported my levin through J-spec. I found Ben to be quite helpful, answering all of my questions. There was some confusion over which car was which... but he stuck with it and got it sorted, made sure the car I wanted was the car I got. (Aside from the condition... the only describable difference was 15 inch Enkei RPF1's.... ).
Car arrived and the clutch was shagged, guy at the compliance workshop was pretty sure it was coz of the guys in Customs\quarantine giving it some 'welcome to Australia' love. It also still had snow chains fitted... front and rear.I had budgeted to replace the clutch anyway....
Not sure if I'll go back to J-spec next time (I'm planning to buy a Manual S2 R33 coupe with the Active LSD later this year), But I wouldn't hesitate to reccomend them, I found Ben to be very honest in his dealings. I will say, I found dealing with them to be really easy, My mate imported his levin through the compliance workshop, and he ended up having to do more ringing around than I did!
Reguardless of who you go through... make it easier on yourself and make sure you've got extra money in case things go wrong, or the ability to get your hands on that $$$$ (Credit card). Nobody likes having to chase you for money. I took the precaution of applying for a credit card when I imported my car.
I was IT Contracting at the time, and as this was over Christmas I had a few weeks with no pay... and then a major stuff up with my pay after that. I ended up not getting paid from the day I paid for my car... until the day before I was due to fly down and collect the car from the compliance workshop (it was in Sydney... I'm on the Sunshine Coast).