Quite possibly you can just keep driving the 240 in winters till one day it demands too much upkeep. Which could be a long time. While a 740/940 may be a good substitute I don't think any other replacement will give you the safety and other benefits you get from a 240. Especially for winter driving.

My son learned about accidents in 240s. I'm very glad that was what he was in. He learned a bit more about accidents in a Hyundai; those repairs were considerably more expensive.

I've also had a few "incidents". Rear-ended three times in 245's. Never more than a scratch on the bumper. You should have seen the other guys though!

This past fall I spun out on a rain-slicked curve on a hill. My fault, going faster than I should have. Whacked a rear corner on a guardrail. The only damage was that the rear quarter panel glass shattered. Bumper corner hit the rail, barely a mark on the bumper. I went up the road to Home Depot and bought duct tape which used to cover the window, inside and out. Drove it like that till I got the glass replaced. Try that in some other car.

Do be aware that around 300-350 km these cars often need these things replaced. If you or the previous owner already did them, you're clear. If not, there's a good chance you'll need them before too long.

Rear trailing arm bushings
Crank position sensor (first used in '89)
in-tank pump, aka transfer pump AND the related fuel level sender
ball joints
rear shocks
front struts

I didn't mention the more usual replacement items that need attention more frequently such as tuneups, brakes, timing belt.
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Sven: '89 245 NA, 951 ECU, expanded air dam, forward belly pan reaches oem belly pan, airbox heater upgraded, E-fan, 205/65-15 at 50 psi, IPD sways, no a/c-p/s belt, E-Codes, amber front corner reflectors, aero front face, quad horns, tach, small clock.