Re: Performance Air Filter
I'm not completely sure to be fair as perhaps like you I'm not mechanic, but;
1) Mainly are they worth using ?
Yes, can be if you get the right sort.
2) Would my dealer fit it for me ?
Hmm, debatable depends if just a replacement that is standard shape for your filter housing rather than induction type that replaces the excess housing/tubing restricting airflow etc.
3) Would it effect my warranty ?
Shouldn't do if it's just the filter (someone may be able to correct me). However if you're looking to get a replacement performance filter that bypasses having the original housing and as such 'modifying' the standard set up, yes I'm sure it would invalidate the warranty.
4) Are they suitable with Diesel engines ?
Not looked into as not had diesel but I'm sure they are. Airflow is important for both!
Hope this helps a little. I know there are quite a few threads on air filters if you do a quick search, but I'm sure someone else can give you better info than I.