I work in a Renault service dept...
To be honest, the Laguna isn't a bad car. BUT...If you get a bad one then you should be afraid!!!
Best advice I can give you would be this...
1. Make sure cambelt kit has been replaced (due every 5 yrs or 72k) or have it done ASAP if you can't verify
2. Ensure the car has proper service history, with correct oil grade used (Renault dealer history would hopefully be fine) to try & avoid possible turbocharger problems
3. Make sure you get a year's MOT with it, that should take care of suspension arms, axle bushes etc
4. Have a decent road test up to motorway speeds to make sure no transmission noises or other issues
I took £1350 from a customer the other day for a major list of stuff on a Laguna of similar age & type, also £900 from another customer, again with similar car for similar list of work.
Get an AA check or something similar done & if in any doubt, walk away, there are loads to choose from.
On the plus side they are a fantastic car to drive, comfy as hell & not too thirsty.
Good luck.