Our DE Stubby lives at 700 ft MSL in Ky. Summer temps can get into the 90's routinely, with high humidity. Don't know what the density altitude of those conditions is off hand, but maybe 1500 - 2000 ft?

Stubby is heavy, but has a good running 2180 engine. With pilot only, it climbs at around 500 - 600 fpm in summer, and, just a couple days ago, with temps around 60 degF, clear and dry, climb was 600 - 800. Even got a couple 1200 fpm boosts from thermals.
We have not flown two persons yet, but hope to do some trials this fall/winter by adding weight to the right seat.
At this time, we think the airplane will carry two with cool weather, but still think it would be border-line in the summer.
I have never gone 8000 ft in Stubby, so I can't say how it would perform at your altitude and conditions.
Les Homan in California has done some serious altitude flying in his LE, and pretty much shown that it should fly well at your altitude.