great work dude.
I think that indeed, the laydown shock-system adds quite some weight to your project ... but on the other hand such a system can quite easely be adjusted so there is a very strong pro to it.
(there MUST be reason why such shocks are used in F1-cars!
)
I think you can easely soften your suspension by making some adjustments to your rockers ... and offcourse to the shocks itselves.
A softer spring, more holes in the piston, thinner oil.
on the rocker: make the distance from the shockhole to the rocker-axle a bit shorter. this way the pushrod will have a larger lever-functionality, IMHO.
Actually, (being an ex-predator-racer) I think that even small changes might make a big difference.
And who knows, maybe just by returning to more conventional shocks (B4, Kyosho, BB TLR22, ...) might get you back on track AND would easy your project.
As what weight is concerned, It is a pitty that the car is this heavy but nowadays, 2WD-cars are often equipped with quite some weight/brass to add on traction with all that heavy brushless-power. A 1700 grams car is no exception anymore.
Also, if, later on, you could replace some other parts by carbon parts, that would drop the weight of the car also.