Is the Lexus IS250 reliable?

[CM2020]

I always thought the IS250 was bullet proof. But today I found reports of carbon build up problems, problems with the cam gear and other issues. I was surprised. I had heard the 220D has lots of problems and is even considered the worst Lexus ever made. But I thought the IS250 was solid? I'm considering one with about 125K miles on the clock. It's a V6 manual. But after reading some of the buyer's guides I became worried.

And do they need to be serviced and worked on at Toyota main dealers or are they somewhat DIY or specialists easy to find?