I always understood you had to use genuine Suzuki filters and have a proper mechanic do the work, but I think this may have changed over time and information on their web site suggests that you don't have to use genuine Suzuki parts anymore. I would email Suzuki to get it from the horses mouth as to whether they will still honour their warranty with self-servicing. This is what I found on their web site:
What are the Terms and Conditions of the new on road motorcycle warranty?
The ‘Terms and Conditions’ are issued with the motorcycle in the Service Booklet, the warranty provided is currently 2 years unlimited mileage
Is the manufacturer's warranty transferable to a new owner?
Yes, the product carries the warranty, not the owner
I have an imported motorcycle from the EU, what's the warranty period?
All European Union motorcycles carry the full 2 years
How do I purchase an extended warranty for my motorcycle?
Please contact your local Authorised Suzuki Dealer
Will Suzuki honour my warranty if my motorcycle is serviced by a non Suzuki Dealer?
Yes, so long as any defects are not the result of any service related issues
If a non Suzuki Dealer services my motorcycle, do they have to use genuine Suzuki parts?
No