Matt,

We are about to remove the V3 from the site tbh, the V4 is just a much better package. It has all the boost control etc already built in which with the V3 its all optional extras. The loom is also better quality, and in general its just a better ECU thats designed to rival the likes of Omex etc in terms of features, reliability and ease of use.

Thats the main reasoning

Matt