got quoted 20k for to replace steel with pex, thinking i can do it myself

for 20k i can buy the tools and some really nice ones at that, buy a ton of piping and just cut and replace.

its only 2 bathrooms washer and dryer and kitchen about 1000sq of house and a crawlspace ive been under to work on electrical... forgive my arrogance but it cant be to difficult to just replace someone else work right?