I've been putting a lot of thought into this car's suspension options, and thought I would share with the group:
(Let me preface this now by stating that I am by no means an expert on suspension, but I have most of the basics down. Also, Dave, this isn't directed at you, mostly the onlookers, but maybe you'll find it of some use.)
Determining spring rates for this car will be more difficult than just buying some GCs and hoping it works - your life rides on these decisions, so a little homework would be appropriate.
You also can't just go out and copy a 98 MR2's setup (TEIN's site lists the spring rate for the Basic and SS @ 220/450, as opposed to the Teg's SS 450/340, we'll get to this in a second... Also, suspend your knowledge of the existence and purpose of sway bars until the end when I'll mention them again...)
Springs are meant to balance the car, maintain ride height, and to counter brake dive / accel. squat.
Noting Dave's planned weight (2500#) and it's distribution (45F/55R), we see that these specs are pretty close to those of the last gen (in the states) MR2's (~26XX-28XX depending upon NA or Turbo, ~42F/58R), or at least close enough for this discussion.
(The MR2 specs were as close as I could get with a bit of digging - MR2 owner's don't have a 'team-MR2' to turn to, how tragic! *L* Anyone with different info from a reliable source, go ahead and let us know!)
Looking at the MR2's springs further, TEIN also offers S-Tech @ 150/270 (vs the Teg's 340/270...) For the S-Tech, the rear rate is 1.8X higher, for the Basic and SS, the rear rate is 2X greater. What can we learn from this?
The higher the rear rate vs the front, regardless of drivetrain layout, the easier it is for the car to rotate (ie more oversteer, less understeer.) TEIN's racier setups allow for racier driving styles/conditions.
If Dave wants an AutoX champ, he'd opt for a greater rear bias, to better be able to swing the rear of the car around. For a daily driver, especially one that needs to be used in foul weather, he may choose to opt for less of a rear bias.
Based on the MR2's specs, and those planned for Dave's car, you might assume springs with ~ 2X greater rear bias would work well - because the car will carry less of a rear weight bias vs the MR2, the car should end up being a little less prone to oversteer than the MR2 with 2X rear spring bias.
However, the Toyota's rates seem low compared to the Teg's rates because of the differences in suspension design. The leverage applied by the suspension onto the spring is different in each car - this Common Topic
offers MD's description of 'wheel rate,' and why it's important.
So, the rates that may be appropriate for the MR2 have no place on the Teg, FWD, RWD, AWD, whatever. Wheel rate of the MR2 must be taken into cosideration when deciding the actual F/R bias, and the wheel rate of the Integra and Prelude's front suspensions must also be considered.
I'm not sure what the actual 'best rates' will be for Dave's car - as I said, I'm no expert. But, if the wheel rate could be determined for the Prelude's front suspension, I would have a good idea of what would be appropriate.
As for swaybars - let's bring them into the party. This Article
explains the purpose of the sway bars - in short, they keep body roll in check. By helping all four contact patches maintain an even level of grip, and by controlling the weight and roll of the body, swaybars have a profound effect on how well a car will rotate, or how likely it is to under/over-steer.
Using the stock front Integra sway, and the stock front Prelude sway in the rear, I don't see this working out really well, TBH.
Because of the newfound weight distribution, the Teg will no longer respond best to the 'little sway up front/big sway in rear' method that is used stock. Having a strong bar AND the majority of the weight in the rear will be oversteer city - between the momentum of the engine/tranny's added weight, and the fact that the stiff rear sway is shifting the car's balance to the front's weak sauce bar, this may well be an amateur drifter's wet dream, but it isn't conducive to lap times or public road safety.
Now, with the Prelude's front sway already in the rear, and the Teg's stock front sway, let's assume they offer about the same resistance to roll - having (~) equally rated sways F/R and a rear weight bias will still offer plenty of tail out action, but it should get itself down the road if driven with care.
Ideally, I think Dave would want to keep the stock Prelude sway in the rear - it is designed to resist the roll inertia of the motor above it, and in general, the rest of the weight around it. The front bar should be replaced with something pretty big - probably a bit bigger than is yet manufactured.
While this entire project is entirely overwhelming to me, the suspension always seemed as if would end up the most daunting part to sort out. Thus, it's the part I'm intrigued with the most, so the previous was my collective thought process, thus far.
For all those thinking this project's final chapter is being written - keep reading. In my book, this is where things get REALLY interesting!
And Dave - Thanks. Your work, stamina, ideas, posts - all of it is greatly appreciated! Hopefully, this post will keep you from having to write up something similar in the future, if nothing else!
PS - Anyone see's anything wrong, or suspect, feel free to point it out - I tried to keep this as fact based as possible, but I'm only human!