Hi there

i recently joined. I am currently driving a 2007 model Opel Astra H OPC. I recently changed my flat bed filter to a performace K&N flat bed filter. I am currently doing 185kw and 355Nm on the fly wheel. I wanna know what other affordable performance mods i can do to the vehicle without voiding my factory warrenty with the dealer.

I am located in South Africa.