Disappointingly, no assembly manual is included (has to be downloaded). No biggie really, but I opened the box excitedly and wanted to read through the assembly steps.
Parts quality looks excellent though, and I really like the front wing setup (has main plastic body with attachable lexan spoiler) 2 different lexan pieces are included ( diff angles for diff downforce) Quite an ingenious tuning aid. Haven't compared side by side to F103/F104 spoiler, but it looks to be compatible.
Can't answer the question 're: springs, as I'm not currently at home with the kit and I haven't downloaded the manual.
Cheers,
Steve