Easiest thing would be to find out what boost pressure you are running, as standard they will hit a boost cut above 0.8 BAR but guess as yours is standard your won't have a boost gauge to find out, other way involves looking at chip to see if it has it written on the top. Theres a lot of good chips out there MSD, Ahmed Bayjoo, Harvey Gibbs to name a few, MSD can post to you easily as well. A stage 1 chip will be fine although I would worry a bit if still on standard Head Gasket. The Sapphires were an executive car but interesting to know about the tax, when new they were more than the 3DR!

Martin