I also have the XP4001. Got it for around $25 at Office Max in clearance. Had to order the additional tip since the cable I bought from Dealextreme would not fit the S7. My $4 2000ma car charger from Ebay on the other hand works perfectly. I used it to try navigation on the S7. Ndrive works great, but I find the S7 way to big. It won't replace my TomTom anytime soon. But I digress.