Interior
My 1995 Infinity J30 is silver with grey interior and wood grain accents and finalized by a touch of black on the dash and instrument panel. I have replaced all the interior lights with blue bulbs that give a subtle blueish white hue to the interior at night... not too blue - just enough to notice.
Exterior
As for the look of the car, the sleek lines and simple colors are complimented by the darker tint I put on the windows and the matching sunroof airdam. The great pearl silver color seems to change in different lighing as you can see in some of the pics.
Sound System
The sound system wich currently occupies my car consists of an Eclipse CD3422 Head Unit which replaces the deplorable factory CD player. The Eclipse connects through the sub out to an A/D/S/ P2110 Amp bridged to 370 x 1 (RMS) powering a custom made 10" DVC Toby sub in a Toby designed box made specifically for that sub. I added two JL TR690-TXi 6x9's in the rear deck and up front is a set of MB Quart RCE-216 6 1/2 Components powered by an A/D/S/ P450.2 amplifier delivering 50 watts RMS to each of 4 channels.
As you can see, the install is very clean. In order to mount the Amplifiers on a solid board, the Auto Restyling Center had to mount a carpeted baffleboard over the exisiting plastic board and secure them both to the brackets surrounding the fuel tank. The result is a very clean looking amp rack with hidden wires that is very securely mounted. Just for fun I had them install ports on either side of the amp rack to give a more dramatic effect and really round out the install.
A closer look at the amplifier mounting shows where you cannot see any of the mounting holes and the only thing really present is the amp wiring. You can see the very thick guage of the power wires because the rated power of thses amps is so understated. The mid/high amp gains are at about 1/4 for the rears and 1/3 for the fronts and it gets incredibly loud without any hint of distortion or speaker pops. Incidentlly, the rumor of turn on/off thump so bound to the A/D/S name is just that - A rumor. I have no thump because the install was done right. The guys who did my install mentioned the rumor and quelled my worry adding that only a good (or lucky)install would eliminate that issue.
Here you can see the Toby Ported Bandpass box housing a Toby 10" Dual Voice Coil subwoofer. This model is called the "Sheriff". The well cosntructed box is carpeted to match my baffleboard. The box is wired with high quality 12 guage cable and banana clips in the multi function wire connectors which can be wired in several configurations to take advantage of the dual voice coils. For more info on Toby subs see thier website at http://www.toby.com - they have great stuff for both home and car audio.
The coolest thing I have done is have a custom wiring job done that allows me to jack in my 10 Gb IPod MP3 player to my Eclipse's auxiliary input so I can play my 1,100+ MP3's through my car stereo and remove the IPod whenever I want to add more songs or play them through a home stereo or anywhere that has coax jacks. Below is a picture of the battery terminal and the fuses used on the two amps.

Performance
Rising Sun Performance has installed a Jim Wolf Tech. reprogrammed Engine Control Unit and Pop Charger induction system. They are a premier Z car modification clinic. Since the J30 has the same engine - the VG30DE - as a 1995 300ZX (Natuarally Aspirated), they are the ones to do it. The upgrades have made a difference in pick up and overall power. It is not overwhelming but noticable, espcially in the initial launch. From the line you can really feel the difference in the 2000- 4500 rpm range when the engine braethes so much easier. The big difference is in the engine sound that now produces a much more throaty and deep intake growl. Even at idle you can hear the hiss of the air being breathed better.
Another difference I have noticed, after a few weeks of driving, is the recalibrated shift points that the new ECU uses. When before you really had to "step on it" to get a good downshift, the accelerator dose not have to be depressed so deeply now. This lends to a much easier drive as you can get into that passing gear or speed up at an on ramp without feeling like you are hot-rodding it. The new ECU also holds the gears a bit longer to give you a bet better power curve and smoother transitions from gear to gear. This combined with the added highway speed power of the Pop Charger combines to make a nicely felt and definitely heard presence of additional horsepower.
Aside from these mods, there is really not much else that will make a dramatic difference without going internal for real serious stuff or dropping in a whole new engine. The exhaust, which I am most seriously considering, will make a small (3 - 6 HP) difference, but will make a much more manly sound than the big-chamber quiet exhaust on it now. I will likely go for a custom designed system with a fully customized cat-back design incporporating mandrel bent pipes and an x-pipe configuration with a Flowmaster multichamber design for maximum flow and minimum noise although really showing its power when you "put your foot in IT".
I was told however that a J30 will accomodate a Twin Turbo engine from the 300ZX that with cheap mods can make up to 600 HP - Damn! What a sleeper that would be.

I run stock size Michelin tires and stock wheels which I am fine with for now. Eventually I may drop the car 1 or 2 inches... but that won't likely come until I get that cash for that and a new set of wheels and tires.

If anyone has any sound or performance reccommendations, please let me know and anyone who may have questions for me don't hesitate to ask.I hope you like my car.