If you're doing the belt, ask them to do the head gaskets too. They fail often on those.
Another reason I think that the Subaru's boxer engine is piss poor. They're smooth and have a low center of gravity but they're a pain in the butt to work on and for that reason, quite expensive. That and they like to eat their own head gaskets on some of them every so often, though I don't remember which ones. A guy I used to work with a guy who had a 2000 (I think) Outback, which he liked. He must have really liked it after pouring a ton of money into it, both head gaskets, belt(s), power steering issues, etc. He apparently had a lot more patience than I.
Speaking of interference engines, my old girlfriend had this one Honda, Prelude I think it was. Kind of a sporty car, well for a Honda of the time. It was slug slow but kinda fun to drive. Anyway, we're running down the freeway at about 75 one afternoon and it starts slowing down. I asked her why she was slowing down and she said she wasn't, but the car was. On the floor, running 62, all it would do. It was a minute or so later and it made a noise and then lots of smoke from the tailpipe. We pulled over and I popped the hood, smoke, steam, coming out of the oil fill hole. I knew it was bad. So anyway, we had to walk a bit to get some cell signal to call a wrecker. Had it towed to a local shop, they pulled the belt cover and the belt broke. Since it was an interference engine, he pulled the head and found 4 broken valves, and with the head of the valve completely broken off of the stem, it destroyed the head, block, and obviously the pistons. The rest of the valves were simply just bent. $4000 later and a new engine, we were back on the way to Florida but we lost a lot of time. Vacation was shortened from 9 days to 2 because of that stupid car. I think belt check interval was every 50,000 miles. I paid a shop to replace it, and it lasted maybe 10k if that. Belts are kind of one of those things where you never know if the slant eye that made it was working a late Friday or an early Monday or mid-day wednesday. Or if he was about 5 years old....timing belts use less power to use them as opposed to chains but they also require replacement every so often.
I just did a 2.3 turbo swap into my Mustang (original Merkur engine) and they are non-interference, so if the belt breaks, it just freewheels to a stop. Replace belt, re-time everything, and off you go. I had a Mustang SVO at one point (same engine) that lost a belt about 150 miles from the house. I walked to a parts store and bought a belt ($9 at the time), and had tools in the hatchback, so I replaced the belt right on the side of the road. Set timing by ear, and it drove all the way back home without a hiccup. Loved that car, and that's actually why I decided to do the 2.3T swap in my '93. It is a crude little pinto engine, 8 valve inline 4, makes about 200 hp. But I still like it.
Ford did use those stupid plastic gears for a few years and honestly they lasted a LONG time as long as they were maintained and the engine wasn't overheated. Once the oil got too hot, the plastic would get brittle. I didn't like them but I've had some with a ton of miles on them; last one was an F150 that the odometer died at 248,000, I replaced the cluster with a brand new one and it showed 213,000 on it when I traded it. Never went into the engine. Had the upper intake off to clean some carbon out, but that was it. And people hated it when they went to OHC V8's in 1997....said that they'd be junk. Couldn't be further from the truth. I'm impressed with 'em and have had 2 or 3 since they came out, all had a ton of miles-and the Lightning had 300k on it when I sold it, all original, and was used every single weekend, both days, on the drag strip...and daily driven Monday through Friday. Great truck. Not real fast, but sure was fun-and super reliable.