My 2007cc motor has 48 Dells, and having run it down the track a few times but never driven it on the street, I can say that they certainly work! The 2276 IDA motor ran 12.09 best, the 2007 Dell motor ran 12.50 in the same car with me babying it because at the time I'd only borrowed it...
It felt smoother to drive around the pits however.