best suspension mod for 355

Lower it!...cheap, easy, looks great and will handle nicely.

 

The 360 springs are for a car with a different weight balance front to rear. Notich how the 306 front wheels are 1 foot farther forward than the F355. And the weight on the nose is up (radiators). So, those springs are not a good starting point.

What is a good starting point is the F355 springs themselves. The spring perches are on threaded collars and can be moved upwards or downwards!

A) If you lower the front too much (or as it slowly lowers itself under the constant weight of the front end) you get to a point where the aerodynamics under the front cause a high speed braking instability.

B) At the rear, you lower the rear to induce understeer, and raise the rear to induce oversteer. There is no particular reason to change anti-roll bars with the kind of suspension geometry the F355 has. You can dial in any particular feel you want.

About the only thing you CANNOT do is to raise the effective wheel rate, and this become necessary when running slicks. When you change to heavlier springs, you will also need to change the shocks to suit the springs. Adding 40% to the effective spring rate is reasonable and useful for r-coumpounded tires (street) or slick on a dual use race/street car. For real race track only work, one can double the front spring rates, and a little over double the rears. Here, it is useful and desireable to ahve a welded in roll cage to increase chassis rigidity.

 

Absolutely forget about stiffer springs or swaybars on a Spider. All you will do is make the doors creak.

The best bang for the buck, on any F355, is an excellent knowledgeable alignment.

This is not the same as a guy who says he does excellent alignments.

Man, if I had a penny for every bad, overpriced alignment I have seen come out of some of the "pro shops"......

 

Well, if you HAVE to get the shocks rebuilt, for no more money you could have them put more viscous damping oil in the shocks and then go up on the spring rate at the same time.

And as long as the suspension is off the car, you might want to seriously consider that its time for new bushings.

 

here's the best mod
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+1
i was going to say, if are original bushes/ball-joints/tie-rod-ends ....then given the cars age now, those are the first things i'd change

rebuilt shocks, or consider that really nice adjustable system (angelis?) posted a thread about in the 348/355 section
...have the springs tested while apart (they do fatigue over time)

finally a really proper alignment (challenge settings)
http://ferrarichat.com/forum/showthread.php?t=319116&highlight=348+alignment

these would make for significant difference IMO

 

What are you trying to do with the car? Street, track, both?

I bought my car with H&R springs installed and originally planned on putting the stock springs back on. However, the car rides really well and handles superbly, to the point I've been among the fastest cars on street tires at the last couple of local autocrosses. I was only beaten by an Evo at the last one. The springs dropped the car about 1.5" from stock.

Aside from that, your best mod will probably be tires. I run Continental Extreme contact DW's on my stock rims and they're quiet and comfortable, but I have a set of Dunlop Direzza Z1*'s on challenge rims and they're worth 2-3 seconds on a 45 second course with no other changes. I don't think there's anything you can do to the suspension that will equal that.

The combination of DW's, HR springs and comfort mode on the suspension is very quiet and comfortable, you could easily drive it all day. The Dunlops and sport mode make it ride like a dump truck on rough roads but it's extremely fast.

 

Lower the 355? I have trouble getting over speed bumps now! I'll keep her stock, though the rear shocks will have to be rebuilt as one is leaking (or did)