It is possible, I'll be installing an alarm this coming weekend so I've been visiting different places in town and most of all can do it. These places are Directed authorized dealers and installers, they can make any Viper or Clifford alarm to work with the ISF, even the SmartStart feature that interacts with your smartphone. There is a module that you'll need for Lexus cars, this module will copy the key fob's frequency so remote start will be possible. In my case I don't need remote start so I'm sticking to a Clifford G5 alarm, better impossible!

 

Watch this...

 

That car in the video doesn't have a push button start.

 

I got a two way alarm remote start from viper 6 months ago. didn't have to give up a key the shop used a module. They had never done an F before soo they just went by how an IS 350 would be wired up. After the install they said some aspects were same and some different than the 350.
The main viper fob needs to be charged like a cell phone..if it runs out and the alarm is set you might have an issue. you still can't lock keys in the car. happy with it so far..never had a clifford alarm..
let us know how you like it. I didn't set up the smart start as I know my cell phone can be hacked easily. Good point about the flat bed truck. I got the viper more for the remote start then the alarm.

 

bestbuy installers/sales rep's = epic fail. they don't know what they're doing. Nuff said! do NOT let them work on your F!!

 

+1 on this... they'll probably take your car on a joyride. Heck, even the dealer I used to go to definitely took my car on a joyride.

 

Viper = Clifford except for the Clifford G5 series. Directed (DEI) own both brands among some others, so they are basically the same thing except for the logo. You can even program a Viper remote with a Clifford brain. G5 is the exception, I believe it was the last project Clifford had before being purchased by DEI, and that series remained exclusive to the Clifford brand. If you want the best alarm you should get a G5, it's not a 2-way alarm and it doesn't have a fancy LCD remote, but it has features that you won't find on other series or brands, not even as options. I had a G5 Intelliguard 770 on my previous ISF and it worked great, I plan to install that same alarm on my 2012 ISF.