We do a lot of Duramax tuning locally and some autocals. We've just recently began tuning Cummins and I find it much easier than a Duramax. We're not overly busy, so we have time to invest. We have access to a local dyno. We also have factory level diagnostic equipment(Snapon Verus Pro with domestic, Asian, and European) as well as drew tech cardaq and Pamler domestic software. We have an online store and that's where we do the majority of our business. We have all Duramax streams and are very pleased with EFILive's progress and ease of use. We're here to help. Cheers