salam ,

i recently owned belta 1000cc , changed oil with zic A+ ,air filter and oil filter.. and now its giving me 11km/L in city ... should i take to toyota showroom and get it tunned up ?? some friends ask me tht jdm cars dont need any type of tunning ,, is it right ???

and secondly i didnt changed thier plugs .. so which plugs should i insert in it and how much it wikk cost me ?? which increase my fuel consumption ..

hopefully u will guide me in the best way .. thnxx guyzz