DV26 is prone to causing stalling when changing gear and coming to a standstill. DV26 will also cause overfuelling on the FRS and can also cause a misfire on hard accelleration. Other probs are the piston sticking causing the dv not to release the air meaning that effectively the car is running without a dv causing turbo stalling.
I suffered from both in my ownership as i bought my car with a dv26 and going back to DV30 was the best decision i made - you'll also find the car performs better with a recirc dv