Here is the lineup of Forzathon events for April:

1. Fooling Around (March 31–April 2)
   • Three by Three: Complete 3 Races in the Morgan 3 Wheeler [or the] Regal Reliant to win 3 Wheelspins.
   • Going Walkies: Perform 30 DRift Skills in a Holden to receive 120,000 CR.
   • Tall Poppies: Complete ANY event to win the Subaru BRAT Horizon Edition.
   • Party Time: Complete 3 Playground Games in the Ford Fiesta XR2 to earn the Lamborghini Sesto Elemento.
2. Spring is Here! (April 7–10)
   1. Sewing Machine: Perform 10 Threading the Needle Skills to receive 50,000 CR.
   2. Back-Half Breakout: Complete 3 Drag Races to earn 55,000 XP.
   3. Pace Yourself: Complete a Race in an AMC car to receive a Barn Find Rumor.
   4. Triple Out: Finish in the Top 3 of an Online Race to win the Dodge Dart Super Stock Horizon Edition.
3. Basket of Goodies (April 14–17)
   • Hopping Good Time: Perform 10 Kangaroo Skills to earn 45,000 XP.
   • King Me!: Complete 3 matches of King to win 3 Wheelspins.
   • Bucket Buffet: Complete 5 Bucket List Challenges to win the Porsche 911 GT3 RS 4.0.
4. Putting on a Show (April 18)
   • Meant To Do That: Perform 10 Crash Landing Skills to win 3 Wheelspins.
   • Dirty Half-Dozen: Perform 6 Trashman Skills to earn 35,000 XP.
   • Can You Believe It?: Perform 3 Two Wheels Skills to receive 80,000 CR.
   • Airborn Hero: Perform an Airborne Pass Skill to win the Porsche 918 Spyder.
5. Show Us What You're Working With (April 21–24)
   • Runnin' Late: Perform 10 Burnout Skills to earn 45,000 XP.
   • Pork Chop: Perform 30 Lumberjack Skills in the Warthog to receive 120,000 CR.
   • Driftworks: Get 3 Stars on 3 Drift Zones to win 3 Wheelspins.
   • Morning Commute: Win a Championship to win the Porsche 959.
6. Horizon Secret Service (April 28–May 1)
   • Car Chase: Complete 3 Flag Rush matches to win 3 Wheelspins.
   • Stirred, Not Shaken: Perform 10 Wreckage Skills in an Aston Martin to earn 55,000 XP.
   • Eye on the Spy: Complete a Championship in the Aston Martin DB5 to win [the] Porsche 911 Turbo 3.3

Note that you do not need to own the Porsche car pack to be able to win any of the Porsche Forzathon cars, as mentioned at the end of Turn 10's announcement of the car pack.

Edit April 7: Added title to the "Spring is Here!" Forzathon.
Edit April 12: Adding the titles and short summaries of the announced April Porsche events.
Edit April 13: Added the first Porsche Forzathon achievements, and a note about not needing the pack to win the cars.
Edit April 14: Added the remaining Porsche Forzathon achievements.