ok.this is it. i have been suspecting this guy. his my friend's friend. he has been rather calculative and knows alot abt car stuffs. ok. i have let him helped me to do headwork and to raise the CR of my car. but i noticed the effects were so so. my other frriend wants me to conduct a check if he really did the job or just plain cheating money. how am i suppose t know if the head has been ported and cr raised? help appreciated. thanks