After
After (note new clear guards in rear too! No more yellowing)
Before
Finally picked up car and went for a 60 mile drive with H&R springs and BB center exhaust.I Started with a fabspeed intake, was ok in terms of sound , then did Gundo hack.... Sounded a bit better but still thought it sounded like a slightly louder lawnmower...added Billy Boat which I got for about 530$ shipped and wow!! The center was the missing link...car sounds awesome. I definitely wouldn't want it any louder and if this car was a daily driver I'm not sure if I would get sick of it...but it's not, and I'm thrilled with final result.

As for the springs, I initially bought Eibach and then decided to buy H and R instead and soooo glad I did. I had a few concerns since the stiock setup feel was so awesome. First, I was concerned about it being to low. I had an old school 300zx that was lowered and it was a PIA. I also didn't want a "floaty or harsh feel" as some stated on here. After driving the car for a while yesterday I thought the 2 mods were awesome in every way. Springs felt almost identical to stock, maybe 10% more stiff but felt way more planted around corners. Was able to easily navigate over some steeper entrances etc. It also transformed the way the car looks, and the wide hips of the 4s look even wider.

My first upgrade was the softronic ECU, I think all the mods made a nice improvement over stock. I've had my c4s for about 18months now...this is the point I usually get bored...but love the car more every time I drive it.....anyone thinking of these mods, definitely do them...they will put a huge smile on your face. Thank you to all who have guided me through the process....

 

Looks great - bet it sounds great too. Height looks just about perfect - not slammed, but better stance, and still very usable. Nice job.