When the one on Babs clubster was repaired it was only the gasket. According to the guy who did the work it's a real bear of a job.
Helix did mine on my R53 and it’s a pain in the ass to do without a lift. Also it is a real ball buster because of the tight area you have to work in.
Just a suggestion, but while you've got it apart you may as well replace your turbo oil lines. That's another common source for leaks on 2nd Gen cars. The DT Super Kit has everything you need to replace the "O" ring/gaskets and turbo oil lines. Much better parts than OEM. https://www.detroittuned.com/dt-turbo-oil-line-super-kit/
Yea I would say do it yourself, and use the difference in cost to do the oil lines like @vetsvette suggested. That way you don’t have to get back in there for some time.
If your going to change those lines (which I would recommend) I would pull the exhaust manifold and turbo off as one assembly. Once you do that the heavens will part and angels will sing as its a lot easier. Changing the gasket without that or putting it in service mode will have you thinking about places further down and a wee bit hotter. Drain the coolant and oil the night before, make sure the mating surfaces are clean and dry. I recommend when you reassemble place a THIN coat of black RTV around the outside of the gasket. Make sure not to get any on the areas inside the seal. Do it right and that place further down will freeze over before it leaks again. Sent from my iPhone using Tapatalk