personally I think the viper remote is too big - I have a code CA670(an audiovox company) which offers all the features you want and more and the remote is about 2/3 the size of the viper's remote.

The viper's 2way delay is a little longer than the ca670's but if you never compared them side by side it wont bother you. But if you are nitpicky it will bother you.

I've installed both and they are both relatively straight forward to install and configure. They both have stock keyfob interface so that you can arm/disarm the alarm with the stock remotes. They both have remote start and manual activation. They both have tons of auxiliary outputs and they both have silent arm/disarm. The code has integrated relays which is a little less mess when installing because hiding the Viper's relay boxes can be cumbersome at times and complicate uninstallation. if you arent installing it yourself it doesnt really matter.

The Codes shock sensor is not as reliable as the vipers - as in it will have more hot spots that are really sensitive and spots that arent and because of that requires more care in placement.

I have disabled the shock sensor entirely on my ca670 and I use a microwave sensor($25 plug n play add on) because it is immune to bass and exhaust false alarms and will trigger warn away even if someone is looking in your windows without touching anything.