I got less than 10k out of my oem dunlops. That included trackdays. Have Toyo T1 sport up front. They are ok but my trackday semislick Advan AO48's are a much stickier tyre. They are 60wear rated though.
Yes it will cause your bearings to wear out faster. I don't think it unsafe though. Just another consumable at the track. Like rotors, pads etc, etc. It's not unknown for guys run big spacers to give a wider track. Given that offset you would still have near on stock clearance from the trailing arm to the rim/tyre ?
Speak to Matt (Floored) of Race Brakes Sydney. I haven't changed my rear pads or rotors yet (26K), but he has been a few dollars of a local/ bloke with anything I've priced.
I got a price pm'd to me from Taleb about same tyre. Response from Taleb was 260 wear. Must be the W tyre. I also want/need the Y rated tyre as that's what the car is rated for. Plus its softer. Think Ozzy had it but they seem to be out of stock ?