Filter: Cartridge, typically a 9018 type if you get FRAM or most other brands.
Oil: Depends....Synthetic or Natural or Blend. Change the natural every 3000, Synthetic every 5000, most people say longer, but I've noticed a huge difference in idleing in hot weather when the oil is getting close to its 5000 mile mark, my coolant gets much hotter much quicker.
Hot weather, go with a thicker weight, like a 10w-50 or 15w-50.
Cold weather, go with a lighter weight, like 5w-40 or 0w-40.
CH9018...It's a really small filter, doesn't even come in a canister like a lot of filters do.
ac delco pf457 filter
Edmunds gave the 2007 Chevy Cobalt Coupe LS decent reviews. They did complain about the car because of how the engine works, but it is fairly a good car.
bosch
My advice would be to use an AC/Delco filter in your Chevy. AC/Delco makes one of the best filters you can buy. Other than that, Purolator or Wix make excellent filters.
It should have a 2.2L L4 engine.
its a closed for life transmition
There are a variety of options for one to purchase accessories for a Chevy Cobalt. One of the best options is the Everything Cobalt site which offers just about any kind of accessory available for the Cobalt. Other options for accessories are Auto Anything and Auto Parts Warehouse.
A/C Delco.
A quality filter such as AC/Delco is the filter your should use.
If you have the regular cobalt you need to use 87 octane gas and if it is the ss with the supercharged engine you use high test.
Look in your owners manual but usually 5w-30.