Guys, I need your opinion.. I have a 93 Nissan B13 1.6 Auto tranny.. How much will I spend changing from matic to manual tranny? Is it worth it?

I'm just thinking ahead, coz this car has been running for 16years and I'm afraid my auto tranny will soon encounter problems...

Could you provide me the parts needed.. clutch disc.... etc... and the price of each... Thank you and hoping to get a reply soon...