The easiest tip on how to wreck other cars easily, try to find powerups like Anvil Launcher or Slaughter Mortar that can deal good amount of damage enough to wreck them, this can also be made much easier when you get the PIS to be able to buy the powerup (cost 2000 credits) and make the wrecking of opponent and unlockables much easier. Whenever you corner the opponet which is stealworthy, fire the powerup at him carefully and with precision, after 1 or 2 hits (deppends if he is already dammaged), he will wreck in a bit and give you his sweet ride. The other way is to get Solid Granite Car and just ram the opponent, this powerup makes your mass so big, you can even wreck tough opponents like Don Dumpster or the Surpressor in only 1 simple hit (Or not, deppends on how hard you hit him). But the most affordable way is using the projectile powerups, since Solid Granite Car costs 1000000 credits. Since the PIS is only obtained on chapter 10, after you get it, try returning back to some early chapters where you didn't unlocked some vehicles to make the task much easier.