What about the TurboSmart range? they do a couple of types that a cheaper

They do electronic 2 stage boost or incar adjustable - also on website.

http://www.rapidford.co.uk/index.php?p0=detail&id=958
http://www.rapidford.co.uk/index.php?p0=detail&id=956

I found when I had the blitz in the saff it had 3 or 4 levels and I always had it on maximum boost or very low for wet weather but rarely changed it TBH

Cheers
Daniel
Rapid Ford