All the quotes I got were around $300 just to replace spark plugs, air filter, and fuel filter. I looked up all these parts and if just bought it was under $60 dollars. I am not a genius when in regards to mechanical workings, but not bad at electrical. I can not see spending that much money for them to throw in parts that I could buy and probably do myself. It is a 5cyl Chevrolet Colorado..2wd. with 60,000 miles. I know air and fuel filter are important and my plugs said they didn't need to be replaced until 100,000 miles. Which items should I buy and how hard would it be to install? Thank you