http://www.ubercart.org/forum/support/12833/untitled#comment-43552

I want to modify the function of ubercart attributes so that the price inputted does not add/subtract to the cost of the base product, but instead entirely changes the cost, setting it to the value specified. I found in ubercart/uc_attribute/uc_attribute.module function _uc_attribute_alter_form() has a line "'price' => $product->sell_price + $option->price," that I changed to "'price' => $option->price," which only visually makes products appear to be less, but when adding to cart it does not take effect. I, of course, want to write my own module to permanently make this change, but I'm not sure where to start to create a module to accomplish that. Any pointers?

Also in ubercart/uc_attribute/uc_attribute.module function uc_attribute_cart_item has
$item->price += $op_prices;
which I changed to
$item->price = $op_prices;

How can I write a module to make these changes permanent so that when upgrading ubercart, they aren't lost?