What installation accesories do I need to install headunit?

[Mills561]

Recently picked up a used Kenwood dnx5120 going in an 02' Chevy Trailblazer

I know I need a dash kit modifier.

It has a wire harness on it, but it probably won't work with my vehicle, correct? How would I be able to find out?

Do I need an antenna adapter? I've read that some GM vehicles need it, how would I find out?

Also, I notice that it doesn't have a mounting sleeve (a.k.a this thing - KENWOOD ORIGINAL MOUNTING SLEEVE DNX5120 - eBay (item 250594623542 end time Jul-08-10 14:23:31 PDT) (http://cgi.ebay.com/KENWOOD-ORIGINAL-MOUNTING-SLEEVE-DNX5120-/250594623542?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3a589a8036) )

Thanks for any help. Am I missing anything?

[AlterEgo99]

Check Crutchfield.com and enter your vehicle make, model and year and then see if your H/U is listed...if it is, they will supply all the parts you'll need to make it fit. Don't buy from them tho as they are full retail. Get the part #'s and then hit eBay, that be what I do.