HVLPs, or any gun, will fall flat on their faces without adequate CFM. If you can get it to spray, the finish will be poor, no matter what the paint's viscosity. PSI and CFM are not to be confused, you need volume. That's why a 3/8" hose and fittings are used in the booth and not 1/4". PPG DPLF is not the same as the better, discontinued DP. For one, LF recommends the use of DX metal treatment or wash primer for adhesion and performance enhancement. People use DPLF without this step, but other epoxies do not call for it. And at the price, DPLF is overkill for suspension components. For the car's exterior, a quality epoxy is best. Everyone has preferences, I use R-M(BASF). U-Tech(Akzo Nobel) is good also. Economy brands such as Transtar and others are used depending on the application.
If you have more paint questions, I'd suggest going to Refinish Network. It's mainly for pros and shop owners but welcomes novices. Car hobby sites have bodyshop forums. But except for a small percentage, most members have no professional experience and the information is often lacking and sometimes incorrect.