Gary Lanzer build the 411 ERYX and has some usefull extra tips when building the car.
Find it here:
http://www.serpent.com/product/400013/tech-tips/
Some of the comments will be used to make the ERYX car and manual even better.
Also Tom from Turkey did a nice write-up on the ERYX car, and you may find it here :
http://www.serpent.com/news/13639/Serpent-41-ERYX-build-report-by-Tom-.html
Team Serpent