Plant upgrade system

In the 5.7.1 update, a new feature was added, allowing the player to level up your plants, make 'em better, faster and stronger!

Overview
Plants are leveled up by collecting seed packets, can be only obtained via Pinãtas. After upgrading plants, the stats of plants are increased, which are sun cost, damage, hp and others. However, not all plants' stats are increased per level. The player has to spend a HUGE amount of coins to upgrade. The maxium level of plants are 20. Now with level up system, instant-kills do more damage, nuts are harder, Potato Mines arms faster, stunning/freezing plants increased time, plant food effects are stronger, expensive plants get cheaper, Coconut Cannons, Banana Launcher and Missile Toe charges faster, very slow recharging plants recharge faster!

Strategies
Don't upgrade plants which you don't prefer to use, only causes a waste of coins.

Trivia

 * Projectile-shooting plants' projectiles' outlook changes by levels.