u should replace it with the red one, the different of basic/ strengthened stats between red/gold are 2-3 times more than a 10% and u have 2 different stats for each tools. 10% bonus of basic stats is around 20pts if u add every same stats together of 12 tools. So if u replace the gold one with red one, the basic math is:

- As i calculated on my level 17 tools

+Lost: 10% = 20 pts. u may lose 20%-30% bonus, equal to 40-60 attribute pts.

+Gain: around 40 points for each stat x2 = 80 pts extra.

- So u can advance further with the red one and it has potential to be activated 5 natures bonuses.

My advice is change ur tools with a better quality. u can check ur tool attribute after upgrade by equip it on and put the old one into strengthening slot. the stats show INCLUDING BOTH BASIC AND STRENGTHENED STATS. I dont have any other low quality tools to show u here but u can check it for urself. This two just an example , the differences are depending on the quality of ur tools and strengthen level. As u can see between 2 pic below, RED quality has 40 pts higher ( 20 x 2) than the EPIC gold.