and i'd like to know if i have to go to the dealer or can i go to a specialists shop. And one more question. I've been using Valvoline 10w 40 in the winter and 10w 30 in the summer. Is it safe to switch to Valvoline Maxlife??

if yes, it might cost ~$700. Otherwise you need need to replace plugs, filters, check/add tran/diff fluid, clean plenum chamber, spray some lube on moon roof etc. Most of it you can do yourself.