Yeah I agree with all the comments above (except about the aftermarket intake, as I’m a believer the stock airbox is the best intake for several reasons). Replace all belts, tensioners, water pump, spark plugs (coil packs not really needed with 70k. That can be easily done later). If it’s an automatic transmission, I would strongly suggest changing the fluid. The owners manual calls it “Lifetime” but that’s not true, it needs to be changed. If you’re going to DIY all the mainteinance on this car, I posted how to do a drain and refill of the transmission to renew the fluid here: https://www.swedespeed.com/posts/7960922/.
Also, If you’re interested in keeping this car for quite and want to make the cooling system near bullet proof, check my signature and click on the do88 silicone hoses link. That will take you to my post about that upgrade. The stock coolant hoses are good, but only will last around 7-10 years before the composite fittings will disintegrate and cause a major leak and most likely the engine demise.
I agree with @88domer, these cars are considerably heavier than its brothers (C30/S40/V50), therefore the suspension is under more stress. IMHO, polyurethane bushings on the lower control arm is the way to go. They make the steering feel tight and precise without causing an uncomfortable ride quality. Another recommended upgrade to not kill rear tires prematurely is adjustable rear upper control arms, this platform is known to have very agressive camber on the rear wheels. While the camber helps to make the car more stable on curves, it does it at the expense of thread life of the tires, so you might want to do this and adjust it to a compromise point between stability and tire life. -1.5° is an ideal point in my opinion.
Now that basic mechanical stuff has been mentioned, we have to mention about the C70-specific stuff. If the car won’t be kept in a garage, you definitely want to set the roof in service position and check all weatherstrips and drains. The weatherstrips, is recommended to clean them first and then treat them with a product called “Gummi pflege stift”. Also, while the roof is open, you want to do the grease all the pivot points (i use WD-40 white lithium grease spray), and check all the headliner cords, make sure they all look ok.
Also, pour water around the tail lights to check for leaks, the gaskets eventually go bad and they can flood the trunk, and guess what is at the lowest point there? Yep, the roof hydraulic pump. For this, I’ll be making a thread later today about how to do a few preventative things to protect the hydraulic pump from potential water damage. Stay tuned.
Just in case, I attached the roof mainteinance instructions.