In connection with the 'lag' problem that seems to happen intermittently using N900 internal GPS with Sygic, I thought I'd just record that I have been using Sygic with a Nokia LD-3W wireless GPS module successfully and there is no lag when using it. Checking the 'Accuracy' stat on the GPS status page in Sygic shows on average an 11yd accuracy using the LD-3W and 25-35yd accuracy using the internal unit.