Just to clarify a few things:
1) The GA5-1 machine you found for $575 (I'm assuming on ebay) is NOT a Techsew sewing machine and does not include reverse, speed reducer, servo motor, u-table, option for smooth feet, warranty, tech support etc.. We are the only ones who sell the Techsew GA5-1R which includes reverse, SmartServo motor, speed reducer, u-table, option for smooth feet, full selection of accessories, warranty, tech support and more.
2) There are no additional tariffs or taxes on top of our shipping prices (unless you live in Canada where there is GST).
3) We've been contacted by people who have purchased the knockoff GA5-1 on ebay and were very disappointed, often looking for parts, motor, feet, needles etc. The servo motor and speed reducer are important components of this machine and are necessary in order to get the machine working to its proper sewing capacity and slow speed.
I recommend that no matter who you purchase from, make sure it's from an established sewing machine dealer who can offer parts, warranty & post-sale support for whichever machine you decide on. An established dealer will also make all the necessary adjustments and inspections prior to shipping it out to make sure it works the way it should.
You can contact any of the sewing machine dealers who sponsor leatherworker.net for more information, Art and Wiz also offer great advice.