Not worth it. Its a really tiny modification, but its an excuse for your insurance company to invalidate your policy or charge a higher premium.
Some insurers are flexible (Adrian Flux?), but others only deal with standard cars full stop - so Id ring them up and ask "if I put an IK on, will it affect my policy?".
If they say itll invalidate the policy, then youve got to decide to put it on anyway, or wait until the end of the year to find another policy.
A number of years ago, I had a mildly moded Clio Mk1 1.2 with big wheels, lowered suspension, IK/exhaust and some colour-coding. Someone crashed into it and then did a runner, so I had to claim. Just before the assessor came to look at it, I put on the old wheels, took off the IK and took out the ICE. All was fine.
Ironically, now Im trying to get my Valver looking as standard as possible!