the most common problem i've seen with the aleros is the hub assemblies ($120 part at advance auto, or auto zone) which you can fix your yourself in about an hour of less. with the 2.4l you shouldn't have many problems if any at all since that was 1 of gm's flagship engine for a VERY long time. i perosnally have owned 2 cars with the 2.4 and NEVER had an engine problem for almost 200k on each car.1 other thing i would suggest is to replace the stock radio asap.you may also have some problems with the lower intake manifold. IF it was a stock part if it has been replaced you should be ok. alot of ppl i know includeing my self had some issues with early on. other then that not much else SHOULD come up. and u have come to the right place to look for info about and help trouble shooting a problem.
oh and welcome to the forums.
raz