What’s the difference besides money between the 1.9:1

The 1.98's make more power than the 1.9's top end, by around an extra 5rwkw. In saying this though, the 1.9 does more power than the 1.98 in the low-end power band. Therefore, unless you take your car close to Redline on a consistent basis then I would recommend going with the 1.9s instead. If you have basic mechanical skills, then you won't have a problem will installation if you take your time. To make the work easier, we also have fitting instructions available.