These are snapshots of Excel Spreadsheets from a Luxembourg-based race team that has a large inventory of Formula 3 parts for sale. There also is a huge list of Hewland ratios for the commonly- used FTR gearbox. The spare parts for the following 2 cars:

2007 Mygale M-07
2005-2007 Dallara F305-F307

This hugely impressive inventory is just from one Formula 3 race team, just one. Globally, there are tons of Formula 3 race teams out there with 100's of Formula 3 cars, and each with their own spare parts packages. And if they don't have what your looking for, you could always order it directly from the manufacturers and receive it within' a few days. Importing Formula 3 cars and equipment over here to North America is of no problem whatsoever and shouldn't be a concern to a potential owner.