My 2c worth.
I had VAP springs fitted some 2.5 years ago now.
I went with VAP because although the Eibachs and H&Rs were cheaper and promised a better (lower) drop/look, my garage entrance has a big dip and the parking stops around here are front splitter killers at the best of times, so I didn't want to go too low.
I also liked the idea of the advertised progressive spring rates.
I've been fairly happy with the look although a bit lower would be nice, and the handling was improved (flatter and less body roll through the twisties).
BUT - it pogoes (bounces) a LOT when encountering dips and yumps in the road at anything over "normal" speed, way more than with the stock springs and Dynamic setting doesn't help, so much so that it feels like I am almost losing control and I need to slow right down.

 

Interesting. I came out of an XKR on 20's (with Dunlops) and dont think that the ride in my F Type on 21's is any harder, once the seat got some flex in it. Not knocking the VAP springs though, if I didnt scrape the plastic thing every few weeks I'd look at them.

 

I had the pogo going on with the H&Rs as well until I reduced the unsprung weight. The pogoing has now disappeared. The issue could be resolved for any wheel/rotor combo if we could find a real adjustable shock as opposed to the OEM 2-way. ( sloppy, and slightly less sloppy)

 

Progressive springs in the past, were less than ideal for performance/track driving. Since the tension in the spring isn't constant, it would make the behavior of the weight of the vehicle which is less than ideal. However, for street driving, they can provide a more comfortable ride while not under load. I'm sure the technology has gotten better but these are some things to consider when picking a spring upgrade (i.e. think about your primary use).

 

That was conventional wisdom when I was racing motorcycles. With spring rate changing by position and damping rates not, there's really only one position where damping is ideal. I'll eventually get my springs installed (VAP progressive rate). Until then, I can only speculate and weigh the reports here. I'm sure technology has improved; in this case, the dampers. Quality dampers make all the difference. These seem decent, but I haven't tracked the car yet.

 

A factory Lotus suspension expert told me the same thing.



For you folks with Dynamic Suspensions on your F-Types,
Could some 'tweak' to the shock settings help? (I haven't ever seen this mentioned, so I don't know if it is possible)

 

An active suspension system is supposed to constantly vary the damping settings as conditions vary. Adjustable damping coil-over systems are available (KW for example) at a price, and I considered these, having suspected the F-Type’s problem was too much compression damping. But a change of spring has given the lie to this - the dynamic performance with VAP springs is extraordinary. The suspension is still stiff, but it absorbs bumps much more effectively whilst the lower stance, particularly the lower rear end, provides improved stability in high-speed bends.

Given the fact that F1 technology has spearheaded active variable suspension technology, I don’t see why a variable-rate spring should be a problem in a sports or racing context...

 

Price.. You can't serious believe that you are going to get F1 performance at consumer prices? Equating F1 technology to what we have at our disposal is a serious stretch.

It really depends on an owners goals. I've raced and tracked cars with linear springs and with progressive springs. Unfortunately, not the same cars and/or dampers to do back to back comparisons so it's not directly apples to apples. Racers still prefer linear springs and that's what the majority use today for dedicated racing/track cars. Granted, no one here uses an F-Type as a dedicated racing/track car so progressive springs won't be a concern. Some people who are more sensitive to 'suspension feel' may notice scenarios like OzXFR mentioned above. Those who are not overly sensitive may never notice. For me, I notice when one tire is .5 psi less than others so it does matter to me. But I also understand that I'm not the typical F-Type owner.

 

I mentioned F1 simply as reference to the principle of active suspensions. Your points about track experiences are interesting and well taken. I too am very sensitive to handling variables, having learned a lot from racing motorcycles and modifying car suspensions - adjustments to the F-Type’s camber and particularly its caster have made significant improvements.

My main point has always been that sports cars don’t need hard suspensions, as Porsche and Lotus demonstrate. And the handling of the F-Type is improved (I think) by a lower stance and better springs. Implicit in this is the shallower caster angle caused by the slightly lowered rear end.

 

I suppose that JLR could have licensed the magnetorheological damper technology, but instead went for a two position valve. Having rebuilt motorcycle shocks and forks before, I gave a passing thought to an oil change in the F-type's dampers. It really was just a passing thought though, as they're not the weak link at present. Once I get to installing my springs I may change my mind. As a side note, I need to measure current clearance as they've just added a new speed bump between home and the rest of the world.

Anyway, there is an abundance of "weights" of oil available in the motorcycling world, so it would be possible to tune the shocks to the spring. If it were a dedicated track car and I had the resources, I'd consider it.

My previous car had a slight deficiency in rebound damping that gave an extra half oscillation on rolling freeway bumps, so I went with Bilsteins. I think I was only at 5K miles on a new car when I did that. I got a little harshness on expansion joints, but anything bigger they absorbed far better than the stock dampers did. I'm sure the stockers would have gotten bouncier with age.