:goodpost:
To add a little after a recent in-depth conversation with one of AXA's managers...
* Any parts originally available from Subaru (like putting STI springs or brakes on WRX), or any part specifically designed for your car but which doesn't change the specs (like a replacement shock from KYB instead of Subaru, but which keeps OEM stock ride height) is fine and doesn't need to be declared.
* Changing the ride-height needs to be declared.
* Different exhaust needs to be declared if the function is changed - I clarified this... apparently if you take away DPF or Cat then you need to declare and will see premium rise... if you put on stainless catback or replacement (highflow sports cat) you need to declare, but clearly state you didn't increase performance but instead got stainless for durability because the factory stuff is less good and stainless last longer (they won't load it for that he said).
* Remap ALWAYS needs to be declared! - They check with all cars if there is an accident he said... however... certain cars won't get a loading if declared properly. The example he gave was JDM cars - declare the remap and explain that it had to be remapped for the poor fuel we get in Ireland compared to the high octane fuel in Japan because else the engine fails. The underwritters know about this now and won't load your policy. If asked if the power is increased don't go there and just say "Nope not as far as I know as just asked them to remap to allow for the fuel here". - They don't check power, all they do with their test is plug in laptop to see if factory ecu settings or changed.
Keep in mind that this is only the advice of a manager in a single insurance company - they may and probably will, have different rules, but maybe still a reasonable guide.