The bike, assuming it's in good condition should sell for around $6k, give or take.
If your Envoy is worth that to you, and you don't mind riding a bike every day, then trade him.
I also don't mind riding in the rain or the cold as I've been doing it for many years. There has been a couple times over the years where I had to ride a bike to work because of simple spur of the moment car troubles(dead battery, didn't feel like changing a flat, ect).
I got my gen2 in May 09. My car at the time died the next day and I chased electrical gremlins for a couple days. It then took over 2 weeks to get the part.
It rained 16 of the next 21 days from the day I got the bike. I had a 52 mile round trip commute to work at the time.
After I fixed the car I didn't want to ride the bike in the rain for quite a while.
You also better have heated gear, or at least heated gloves, for temperatures in the low 40's and below. Especially once the sun has gone down.
Riding a bike every day is fun, but it can get be hassle getting gear on and off for work. It's nice to just get in the truck and crank the heat when it's cold, or stay dry when it's raining. Or AC when it's hot and humid outside.
If you're questioning yourself, you're not a die hard daily rider regardless of weather.
Swap for the bike and buy a p.o.s car to get you from A to B when you don't want to face the weather.
A lot of variables that weren't given so its hard to say...... Where do you live because weather could be a factor. Its not bad to ride in the rain but what if you have to put on some nice clothes for an occasion? Can't show up soggy or sweaty...... Do you have the money for a beater car? Do you have have other people in your houshold that depend on reliable transportation? Can't put a car seat on a gsxr750 if you have other means of transportation on can borrow 1 then maybe but @ some point in time you Will need something with seats and a roof............