Many thanks for all your ideas, I'm not really clear on my best way forwards so appreciate the thoughts.
My past experiences have somewhat put me off coilovers, and HSD coilovers in particular. (Sorry, long rambling post follows.)
When I was living in Japan I bought an S13 Silvia, which looked great lowered on 16" SSRs by some bright-orange coilovers. But the ride was appallingly bouncy, really useless on anything other than a dead smooth road, banging-head-on-roof bad. I chucked them for some low-mileage stock suspension. The car looked worse but drove much better, especially as the garage set the geometry up really nicely.
Having been parted with my lovely Silvia abruptly on returning to the UK, I imported a 180SX, bone stock. I bought Driftworks HSD coilovers, with softer 6/4 springs, plus new adjustable arms, and took it to Wheels in Motion to set up & align. The car just never settled on the road, it was always fidgeting and lost traction really easily. I then got some KYB AGX (?) dampers with lowering springs and it was a lot better, a reasonable compromise but not great.
Ultimately over five different S13 suspension setups, I felt I'd not really found anything that made the car flow over a good B-road as well as, say, a Peugeot 306. In fact part of the reason for buying an FD was this, I was disillusioned with trying to make an S13 handle & ride properly by buying and then discarding expensive aftermarket parts, I thought I'd buy a car with good handling out of the box.
So, that's a longwinded way of saying that I'm not
that keen on buying HSD or similar £700 coilovers; albeit I know that it's a way of getting a matched set of brand new springs and dampers all round.
If these two threads are to be believed, stock FD springs are 4.8 kg/mm front and 3.6 kg/mm rear, approx 25% stiffer front springs give an equal wheel rate front to rear, as the motion ratio differs.
Suspension/Wheels/Tires/Brakes - "Best" Ohlins spring rates? - Hey out there- Well, my '93 is coming along...the engine Rob @ Pineapple built is pretty well sorted, almost broken in. She's shod with RPF1's, 18x9.5 w/255/35 Michelin Super Sports all around, and Ohlins DFV's with the stock 11kg...
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Suspension/Wheels/Tires/Brakes - Spring rate vs Ride comfort vs Performance database (FD3S) - Hi guys, I have apexi N1 pro coilovers on my FD with 12 kg/mm in front and rear. It's too harsh for the streets around here. I'm looking to replace my current springs or my coilovers. While looking...
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So 8/6 is quite a step up in spring rate, although many people say that great damping takes the sting out of heavier-rate springs.
For sure the stock FD rolls noticeably in corners, my understanding is that with the low cg and double-wishbone camber gain, the roll shouldn't affect cornering speeds that much, and that Mazda deliberately design the suspension this way, similar to the MX-5s.
Does anyone have first-hand experience of Bilstein B6, KYB Excel-G or the Tokicos ? These are looking like my best bets to stay with the stock springs, I think.
I've even considered splashing out on something expensive like Ohlins - but expensive options seem to come with even stiffer springs (11 kg/mm both ends), so seem unlikely to deliver a smooth, flowing ride on uneven B-roads.