Had a 1999 Tahoe with the classic intake leak. Also had, and have, access to two GM certified mechanics who work for an independent shop. At the time, 2002, it was a really pricey repair. OTOH, their shop made a shit ton of money replacing engines that only lasted a few weeks after other, less qualified shops had done the same work on GM vehicles. The biggest issue is that the mechanic has to meticuliously scrape and clean the top of the block, while being obsessed with keeping ANY debris from dropping into the engine. Let a little bit of trash drop into the motor, and it's all over. I do a lot of work to my own vehicles, but this is one job I would leave to a mechanic that I know is experienced and trustworthy.