From what I know, yes, if you spray, the warranty is void. I agree it's as ugly as sin. The Focus is a pretty ugly car anyway. Additionally, (I may be wrong here..second hand info) but I believe Saleen started with a ZX3 as its base, not a SVT Focus. Seeing as how I bought my SVTF for less than 16K brand new, you are better off going that route and slapping in your own bottle, or better yet Jackson S/C. Also, The standard ZTEC engine in the ZX3 isn't built to the specs that the SVT's poweplant is so running the bottle a lot probably isn't that good an idea.
I'm no expert, and I'm biased, but if anyone was considering the Saleen, one might want to go with the SVTF instead. By the way, this is the last year. Future collectable? Mmmm...Probably not.