If it doesn't have spark after replacing all those parts, you're looking at a possible wiring problem, computer issue, or crank/cam sensor problem. If it does have spark, you're probably not getting enough fuel pressure or you have a timing problem.
GM Dealer Technician For 18+ Years In the automotive industry for 20+
No spark, check for voltage at the coil positive terminal when the ignition key is on. Battery problems are the number-one reason of no-start condition. Check your battery is to turn your headlights on. If the headlights come on and are nice and bright, not dim or dull, then it's likely your battery and its connections are okay.