By all means ignore a sponsor telling you to chuck 1k at coils, seriously wtf, get out.
Here's my take. My M is high miles and I do all my own work. Like the above said, start with the basics (cheap). 1) Check your codes, 2) if it hasn't been done recently, inspect and replace your air filter, fuel filter, spark plugs. You can do all of that for under 100 bucks. 3) clean your MAF, cost is MAF cleaner and takes 5 minutes, 4) throw a bottle of techron in the gas tank, cost is 1 bottle of techron, 5) remove intake manifold and clean throttle bodies (if needed), cost is the cost of the pliers needed for the throttle body boots and whatever you use to clean them, 6) consider removing your fuel injectors and having them cleaned, costs about 100 bucks to have them done professionally, 7) inspect your valves, I did this last week and only had 3 valves very slightly out of spec after 50k mi, no noticeable change in performance.
Thats my .02. Notice I'm not recommending upgrades. These are just things I do to restore lost hp.
Edit: I DID replace my MAF for causing hesitation issues a year ago, BUT I did have a MAF code.
Here's my take. My M is high miles and I do all my own work. Like the above said, start with the basics (cheap). 1) Check your codes, 2) if it hasn't been done recently, inspect and replace your air filter, fuel filter, spark plugs. You can do all of that for under 100 bucks. 3) clean your MAF, cost is MAF cleaner and takes 5 minutes, 4) throw a bottle of techron in the gas tank, cost is 1 bottle of techron, 5) remove intake manifold and clean throttle bodies (if needed), cost is the cost of the pliers needed for the throttle body boots and whatever you use to clean them, 6) consider removing your fuel injectors and having them cleaned, costs about 100 bucks to have them done professionally, 7) inspect your valves, I did this last week and only had 3 valves very slightly out of spec after 50k mi, no noticeable change in performance.
Thats my .02. Notice I'm not recommending upgrades. These are just things I do to restore lost hp.
Edit: I DID replace my MAF for causing hesitation issues a year ago, BUT I did have a MAF code.
