WELD IT. That's what the pro's do. This is a :20 min job.
Get a $25 soldering iron that is going to be your plastic welder from now on and you just saved $800. Then create an extra support with epoxies like JB Weld.
I have not found any glue alone to work on that ABS.
So, plastic welding is super easy. Sand just the paint away no mater what you do. Don't make the plastic thinner. If you get an adjustable soldering iron, turn it way down and experiment with what temp melts that plastic without making it smoke too much. If you make it too hot and it bubbles, you've changed the chemistry and the plastic is toast.
Lower temp is better.
Hold the broken pieces together and use the soldering iron to fold together the melting seems. They may become a little thinner where you welded so, you can rob a little extra plastic from other places like here:
and make your weld stronger. BUT MAKE SURE YOU KEEP IT THE SAME SHAPE if it's a part that has to fit together again. Just use the soldering iron to melt a little piece off and put it on the seam where you are welding. Fold the melting plastic together in small sections holding it all in place.
If you want you can create a support inside a majorly damaged piece like a fully smashed side from a crash. Tape the parts together on the outside so they are perfectly together, then ONLY weld the INSIDE as deep as you can go up to the paint. Inside, get all paint off & sand it very rough. (If it's really bad, you have to weld outside and in, then sand and paint.) Then gets some cloth, fiberglass, or carbon fiber (BEST), massage in some JB Weld, and lay on the resin soaked fiber on your part. 24hrs later you can putty, primer, paint that part and you just saved $ hundreds. MAKE SURE YOU'RE NOT MAKING BULKY PARTS THAT CONFLICT WITH YOUR BIKE. Check the clearance of where that part goes before you start. Those tabs, for example, need to be the same thickness or they're not going to fit together again. Also why glue doesn't work on a thing like that. Welding at low temps will be strong enough to work again.