FYI, Katzkin or Roadwire leather seat conversion kits when done by a licensed facility like ours do NOT void the warranty in any way whatsoever. We do 3-5 of these leather kits for Nissan alone per week. Probably half of those being Altima's. They carry a one million dollar liability policy and we have never triggered an airbag light or system malfunction with installation. These aftermarket seat covers are built to EXCEED OEM specs across the board. As a matter of fact, many Nissan dealers prefer them over the OEM leather because they actually tend to hold up better. The leather is dyed all the way through so when the car gets many years on it, and the customer does not keep protectant on it, and it eventually begins to crack, the aftermarket leathers have the same color underneath. The factory leather is white underneath and looks horrible when it starts to age.
And the install on the first Altima listed here looks okay. However, I probably have over a hundred pics that we have taken in the last couple of years on Altimas alone and you can see that when a real pro that does this all day long installs one of these kits, they fit better than OEM. If there are any wrinkles, most are steamed out by the professional installer so that when the customer takes delivery at the end of the day, it looks flawless. Take a swing by our myspace page
http://www.myspace.com/mcorautomotive and flip through some of the pic galleries to see what I mean.
Pricing? You shoud pay no more than about $700 for a carry out kit if you can find a dealer who will sell it to you (NOT for the average DIY'er), or $899 installed. If you add two tone price in about $50-$100 and contrast double stitching is actually free for the authorized shop so most will not charge extra for it. Average install time on a Altima for my lead upholsteror is about 6 hours begining to end.
Here is a Maxima (some befores and afters):
Here is a Murano:
Here is a Rogue:
Here is a Sentra (some befores and afters):