Here is what I run in a Grand Caravan and Crysler has a service Bulletin out that has a lot of usefull information on installing Mobile radios and Antennas and they say in it that a guy should to a hard install when it comes to mounting the Antenna and not to worry about the value going to shit when you drill a hole. I showed that to my other half and once she read that I was good to go and I'm glad I found that bulletin too.
I'm running a Mr.Coily Comp Antenna mounted about 12" from the seam on the back tail gate or the rear spoiler and I also used a Mr.Coily mount and used a Hank BreadLoves Brass Ball Quick Release Mount which makes it nice to have so you can drop that Antenna down in less than 30 seconds when you need to or get in the Garage with it.
For radio right now I'm running a Galaxy 99V with a Old School Messenger M1200 Amplifier and that set up really works nice with that van.
I also switched out the factory stereo and speakers with a Double DIN Kenwood Excelon DNX8120 DVD receiver with Built-in Navigation and Bluetooth. I also added a couple swivel headrest monitors and tied them into the Kenwood DNX8120 and installed 3 sets of the Boston Acoustic Pro 60's Speakers the fit perfect in place of the factory Infinity speakers, so when ever I sale the vehicle I can put the factory speakers back in.
I also added a couple Boston Acoustic Amplifiers a GT-4100 and a GT-475 and also installed The Infinity Bass Link 10" Enclosed Power Subwoofer that fits real nice behind the rear back seat that is only 5" deep and don't take up much room and with both of those set ups installed I don't have any problems at all.
Just make sure you take your time doing the install and don't cut any corners when your at it and you wont have any problems but I know it was well worth the hard work and it took me about 5 days to do the install and the van didn't move until I was finished. I started by removing all the interior which is easy to do everything just snaps inplace except the front seats and they were bolted down but easy to get access to the bolts. Then I removed the Headliner and that was easy to do also once I had the seats out and while everything was out and after I had everything installed I dyno matted the roof and sides including the doors and pillers and also did the floor before I put the carpet back in and what a difference all that made and really make the interior very quiet and you don't pick up any road noice or wind noisy like it did before that and I didn't think it was too bad too begin with untill after I did the install and was finished with everything and could tell the difference and I was glad I did all that because I would of never went back and did the dyno matt I know that. That is what I mean by not cutting any corners and it was well worth all the time and effort I spent doing the install.
I also upgraded the Alternator to a 250 amp Alternator and upgraded the Battery and ground cables to 4 gauge and re did all the grounds and added more grounds including all the doors and back tail gate too. I'm sure there was more but this gives you a idea anyways.
Cotton Mouth.