Tiida868: 2006 Tiida E4WD

Welcome to the forums!

Lowering your car will not compromise your suspension if you used the correct parts. If you want a mild drop go for lowering springs, but if you want to hug the ground I would get coil overs. Never get super short springs to replace coil overs, that would destroy your struts.
As for the coil over options there are a few to choose from:
-TEIN
-Tanabe
-D2
-KSport
-(I used to believe there was a Nissan coil over at Bob's but my memory is hazy on that)

I'm sure that there is one or two that I missed.

Well there's a handful on the market
-Eibach's
-Tanabe
-TEIN
-Megan
-H&R

Personally I'll go with either TEIN or Eibach's since I had first hand experience with them and their spring and ride quality is top notch. I also have heard many great things from Tanabe. Megan springs seem to have a mix review, some people hate it while others love it. H&R, have zero clue who has them and their quality.

A word of caution though, expect you car to ride a bit bumpier and rougher when lowered.

EDIT: In the end most of the lowering springs will do the same 1.5 - 2.5 inch drop.

Hi Tiida 868.

Welcome.

It is interesting to note the existence of electronic four wheel drive Tiidas. It seems that they were available in some markets, such as Japan, Australia, the Caribean, and some others for 2006 and 2007.

We learn something new every day.

I live in Mexico and I wish I could RAISE my car a few cms because of all the speed bumps and potholes.

Cheers!