Looking at taking a class in Conn with an AR from out of state is this possible?

you can't
Unless you previously registered it as an assault weapon here in Ct prior to our AWB. you can not bring it here to train with. If you are a Leo - you can. Military as well.

If you take a class with a friend who is a resident you can use one of his guns, I think?

Is the AR a "preban"? In other words was the AR manufactured PRIOR to September 13, 1994? And if it was is it on the banned by name list?

If it is not on the band by name list in the link above and was manufactured prior to 9/13/94 it might be possible/legal (depending on how one interprets the stupid laws) to bring the AR in. Anything manufactured after that date would need to have been registered with the state prior to 1/1/14 (certain exemptions apply). Any firearm consitered an assault weapon by the state has to be transported in a specific manor.

Also, keep in mind magazines holding more than 10 rounds are also banned here now (again, certain exemptions apply). No such thing as "preban" magazines.

Also, keep in mind you cannot buy ammunition or ammunition magazines in CT unless you have one of the state issued permits/certificates.

Might be worth checking to see if the company hosting the training can provide you with a firearm, that way you can avoid any issues.

Ended up doing the above great class learned a  lot in the short time.

Might I ask what class did you take and who put it on?

Thunderdome (Low light pistol and rifle) at King33

That's a bitchin class.

There is another one Sunday.

I've said it multiple times, I need to get some training!

We all do, sadly I burned most of my training budget for the year in only six days  at Sig Academy in May

By far the best training I've taken.