GST on Vehicle sold

My friend is engaged in vehicle body building and interior works. He has purchased a van from the showroom and modified the vehicle as per the customer's request with proper interior & exterior work including refrigeration etc(vending van).  

1. Now my question is whether he can avail input on the purchase of the van.

2. What is the rate of GST applicable on the sale of Modified Van.

Thanks and regards,

Gopalkrishna