I'm in a team, but I wouldn't call it super serious. We're relatively small. The competition I qualified for had competitors from 3/4 different teams competing, but it was not a team based event. Everyone was in it for themself, and for the $15,000 reward.
GT4 is fun, I picked up the 718 recently and prefer it a lot more over the perculiar Mclaren and boaty Aston Martin. I much prefer prototypes, with a P5 finish in last years Watkins 6hrs in LMP2 and hopes to make 3 of the 4 timeslots in LMP3, LMP2 and GTP this year. Eagerly awaiting the PS320 and V-Series.R! I do a /lot/ of league racing primarily, and help run a few in a community of 200.
https://gabirmotors.com/tools/specmapping
I recommend this webtool if you're into livery making