The S is off centre so there's no need for a new badge - just pick it off and use polish to remove the remnants
The 2.5's still a quick car, but unless it's 1.5 seconds quicker to 60mph and 60bhp more than stock then I'm not sure about it running with an S without an issue! Still a great car though don't get me wrong. I just wasn't sure if that was you justifying keeping the 'S'
Very jealous of that centre console and red belts though. What's your plans?