How To Automatically Update A Macro To Adjust For Rows Being Added

I have a worksheet used for a car game. Each row is designated to show one particular car that can be used in the game, so let's say that there are 40 cars taking up 40 rows.

Column A shows the car type and model; column B shows the engine that the cars has represented by a number (the higher the number the better the engine is); and so it continues, Column C shows the transmission; column D the brakes etc.

Underneath the 40 rows (lets say from row 45 to 65) I then have a table with spare-parts that can be used to replace the cars existing parts. This Parts-table is also arranged with engines in column B, transmissions in column C, brakes in column D etc...

This point of this layout is that it should be easy to compare each type of part in the spare-parts table with the corresponding type of part already used in any of the cars as everything is perfectly lined up by the columns.

About the spare-parts table: because the inventory in the spare-parts table often are added to or subtracted from, as parts are won in races or being put on the cars, I have created a macro to sort the parts in each column so as to put the best parts at the top of the table and the bad ones towards the bottom - so far so good.

The problem is this - as I add new cars, the table of spare-parts is pushed down worksheet and that means that the macro no longer will reference the right rows. So the question is this, how do I automatically update the macro to adjust for rows being added above it? I am not really interested in redesigning the worksheet.