Just to add to this; I've been researching both locostusa and Keith Tanner's build site.
The vast majority of people Stateside have had issues with the track rods fouling the lower wishbone. There are several reported ways of tackling this...
1 - straighten the steering arm so that it's horizontal, then ream to take a TRE from the top. Don't like the idea of this as you'll probably have to heat the arm, so the upright could be fatigued as a result of this.
2 - a mark 2 MX5 upright has raised steering arms compared to the mark 1 (7mm difference). The TRE would fit as OEM. There should be enough adjustment in the steering design to remove any bump steer that this might dial in. The 7mm may be enough to provide sufficient clearance. This is how Keith Tanner did it after trying rose joints on mark 1 uprights.
3 - remodel the front edge of the lower wishbone to clear the steering rack completely. This is how it is on a MX5.
Looking at the way Nathan has done it, I would be tempted to try a MX5 TRE instead of a Ford item in that situation. The cranked end of the TRE would bring the track rod down a bit, should still provide sufficient clearance for the lower wishbone and might reduce the amount of bump steer introduced by doing this.
Here's an article I found on bump steer -
http://www.longacreracing.com/articles/art.asp?ARTID=13
Any thoughts?