+1 JMD
You can do whatever but the restrictive standard exhaust is the key issue with pinking. If you haven't had the cam drive fully upgraded have a look at Andrew Warrens excellent guide to what you should have and how to identify what you do have.
https://www.mtwc.co.uk/wp-content/u...Pulley-Replacement-Ver-1.compressed.pdf. If it is up to the most recent specification it should be reliable, other than some possible dodgy cam belts that seem to be about.
