I have a question.

1.if i retard the timing does it help performance ( what are the ups and downs )
2.How would i do tthat?

 

I wouldnt bother unless you have an aftermarket cam. Retarding the cam puts an emphasis on top end power. You can do it one of two ways. Buy an aftermarket adjustable cam sprocket, or put another notch in the one you have. Both of which require a degree wheel and some know how.