i have run mine until this week, finally had to get rid of it though... the kenne bell flows much better lol. MAybe i was lucky, but mine never cracked and i live in WV--lots of hot lots of cold.
Dont backfire any nitrous? honestly i would not pay for the aftermarket intakes unless you are gonna do some supercharging or spray.
Get some subframe connectors (kenny brown maybe) and lower control arms to help out with those new shocks and you will notice a big difference in the car. MMR has always been good to me for suspension and drivetrain.
these plastic intakes do not just crack at the alternator bracket bolt points. They crack anywhere along that front water crossover. We just had one that split on the bottom. Poured water but you could not see the crack until we got the intake off. The water is hot enough, and if you are not careful about changing antifreeze as recommended, it gets acidic enough that it will eat away the inside of that crossover passage and cause a leak. My son's blew out one night the same way and he had to have it towed home, it leaked so badly you could not fill the radiator completely full, and driving it was impossible as it lost water too quickly...
It is worthwhile to replace it, and a good replacement can be had for $200 at Westwood (dorman)