If you are looking for a new antenna, and plan on other radio's in the future, The Comet CA-2 X 4 SR is a wide band antenna that will work with the Amateur VHF/UHF frequency's as well as GMRS.
It has decent gain and good SWR with either Amateur VHF/UHF or GMRS.
I use the Comet the majority of the time, but also carry a Larson 1/4 wave that I can switch to when I want a lower profile antenna or are near the mountains or repeaters up a lot higher than a valley floor.
The Comet is a heavy antenna, that does fold over, so it really should be mounted to an NMO fixed mount.
If your just looking for a 2 meter antenna, you'll never go wrong with a Larson. They make a 1/4 wave and 5/8 wave antenna. They are light and are some of the best on the market, the 5/8 wave will have gain.
One other thing to consider. If you live in a hilly area, sometimes the best antenna is a 1/4 wave. If it's a flatter area, than an antenna such as the 5/8 wave Larson or the Comet would be a good choice.
Unless it's a brand new car that you plan on reselling quickly, a hole in the roof will make no difference when you go to sell your vehicle, just buy a plastic cap to go in the hole in the roof when you remove the NMO mount.
If the car is newer, it's many times best to go to a radio shop and pay to have it installed properly. An older vehicle without airbags, just remove the headliner so you can find the best place to drill the hole, remove paint from the inside so the NMO mount can get good metal to metal contact.
An antenna mounted directly to the vehicle will do quite a bit better than a mag mount and you can usually get lower SWR also.
The antenna is the heart of any radio system, going cheap is a sure way to disappointment.
Also, use nothing less than 8 Ga. wire from your battery to the radio. A lot of voltage is lost in wire.
Be sure to use a grommet where the wire goes through the firewall and fuse the wire at the battery.
73's John KF7VXA