SPI Brand is a good product,the epoxy primer is actually sandable in 12 hours and doesn't get gummy like some other lead free epoxies.I use it a lot on motorcycle frames and the under side of fenders.The clears are god as well,I use the production clear on smaller jobs.They have a nice Matte Black single stage urethane paint too,gloss or lack of is adjustable with actvator.
A great direct to metalprimer is House of Kolor's KD3000 series.It can be a high build primer with no reduction,a medium build with single reduction or a sealer under HOK paints by reducing it twice.Lays down level and sands great.
RT

My painter loves SPI clear and their primers. They keep their prices in check by not sponsoring everything in sight, which costs $$$$, PPG even sponsors motocross racers despite that dirt bikes have no painted parts. All that advertising money going out means they have to charge more money to cover it.