1:8 Buggy - fast rally setting

Kyosho Inferno Neo Racing Spec gonna to make it a fast onroad/rally car, target speed as FA's as Kyosho stock GT2, possible?
- 2 speed clutch, seems not possible;
- rally tire, ready;
- engine, just changed to GO .21 but found it heavier than stock KE 25!
- pinion, changed from stock 15T to 18T but a bit heavier than stock!
- front/rear spring: thinking about a shorter and harder one, any recommendation?
- body weight, any idea to further reduce it?

As Neo is lighter than GT2 though it's no 2 speed transmission, I hope simple mod my Neo can make it as fast as Kyosho GT2.   If really possible, my next big question would be...how to get a body shell to make it looks like a rally/touring car!!!  Just for fun....

Where do u race the NEO?

I'm not racer, mainly rough concrete road / short grass / car park.

Easy way:

Use 18T + .28 engine + Kyosho GT2 body mount set + GT2 front bumper + GT1 body

Thanks Ching.