its just a word of mouth safety thing to keep it under this incase they start to delaminate the ceramic coating
you wont need to run any more than 10 - 12 anyway for the time being - focus on getting your exhaust right - and definanatly look at removing and changing to a frontmount setup . They are now the first two things id be advising to look at if you want a little go .
Then , maye when you have some playcash = get your ct26 upgraded and highflowed with steel wheels , or look at something aftermarket..
( of course aftermarket ecu will ultimately help you get more go too - pop in on the gt4 dedicated thread - theres tonnes of info being gathered in there if you wanna gave a good read