As noted it is your choice really. But for around $5K you should be able to get EVERYTHING done, new exhaust bellow (always leak), new gaskets, possible new hpop, turbo cleanout etc. Find a good recommended independent shop, not a 'dealer' to work with. I have found a ford tech who does side jobs and he is reasonable and when last worked on my truck brought it up to all the latest tsb's that applied to it. Just saw tacoma (i know not same) but on used lot at $43K! dont know but that was pricey just for a name. Have seen used diesels for less but 'buying' used is really just getting a pig in a poke as you have no knowledge of its 'real' history. BIL has a friend who got a good deal on fairly new dodge/ram, ran good but soon was a nightmare. Guess it came out of texas and had been submerged in salt water or? and all electronics became toast, engine evidently had some water also in it, but it was a 'good deal'! Anyhow guy had to get rid of it and bought a suv of some sort.
Bottom line is you know what you have and with a little searching can find someone to do a good job at reasonable cost to you. Interiors can be upgraded with new seats out of salvage yards etc again not all that expensive if you can do work yourself.