This question has been bugging me for the past 48 hours since I experienced a lot of lag while playing on DSi, playing with friends via Download Play. Here's the story: I tried my friend's DSi and 5 of us played Mario Kart DS. The host uses an R4 flash cart on a DS Lite and I'm connected via Download Play. Sometimes, the wireless strength goes down which leads me to thinking that the DSi sometimes gets laggy when communicating with Lites and Phats. Since I am planning to get a DSi soon (started to love it), I have a few questions so I am assured that I will be making the right purchase soon. 1) Do the flash carts work well on the DSi? Has any of you experienced any minor problems (games can't connect to WiFi, frequent disconnections, etc.) while using flash carts with the DSi? 2) Has any of you also experienced lag while playing on the DSi against people on DS Lites using Download Play? 3) Are there known problems while using flash carts? I'm asking about DSi flash carts just so you know.