Procharger all the way,all the blowers have thier little problems,Procharger had some seal problems in past years but they seem to have been worked out now.Havent seen any problems for some time now,we have guys running smallblock powerplants with the D1 head units as well as the F1,both are great depending on your application.If you have a good forged bottem end,good heads,and the right cam you can make monster power.I wil say that vortech has some nice carb hats and coolers that can work well with that procharger head unit.Like some of the others said just make sure that you have the fuel system to support the power you wish to make.And a blower specific carb will also be a huge help.