Yeah will work with key+immo+ecu but you will also need to swap the key barrel on the steering column to match the new key.
Im pretty sure the k3-ve2 is limited to 7000rpm
If you need to raise the rev limit more your than that your options are aftermarket ecu or overclocking the standard ecu.
I will do this to my ecu, I have ordered a 4.194304Mhz crystal from this ebay seller https://m.ebay.de/itm/1x-5x-Alle-Frequenzen-40-3-579545-bis-48-MHz-41-Quarz-HC49-THT-Crystal-/322906724265?varId=512030570825&txnId=1868437788011
It is approx. 5% faster than the normal 4Mhz crystal
This will raise my rev limit to about 7350Rpm.
It works by speeding up the internal clock in the ecu, basically makes the ecu think 57seconds is 1 minute instead of 60 seconds, so the ecu thinks 7350rpm is actually 7000rpm or 5250rpm is actually 5000rpm for example . The downside is the ecu is using the fuel and ignition values for 7000rpm when the motor is actually doing 7350rpm.
It can lead to the motor leaning out if you take it too far and put in a crystal that is 15 or 20% faster to try and raise the limit to 8000 or something ridiculous.
Just something for you to look into if your looking for more than 7k but dont want to pay for an aftermarket ecu.
I have been thinking doing the same thing to my Sirion K3-VE. change over the K3-VE2 cams and ECU. what cams are you running? @Mick I think the K3-VE runs more than 7000 RPM, Max power is at 7000 and red line is shown at 7500 rpm.