For a 98' I think the Ultra Gauge is better than the Scangauge , has a better display.
and for less than 1/2 the price its a no brainer.
As far as the Kiwi, looks like the Ultra Gauge is still a better option, $30 cheaper and appears that people like the UltraGauge much more in reviews.
I like mine, have no complaints about it at all.