I was meaning to start a thread with a review but Ill just add to this.
I had the same issues as the OP and decided I would start with what some say is the last resort. I pulled my valve body and took it in to
http://www.txchange.com/ for a Transgo shift kit (
http://www.transgo.com/rpg_nissan.php). The reason I did this first is because it was something that I wanted to do even if it didnt fix the slipping. I was then going to get the solenoids and/or TCM next. But as it turns out, it fixed my flaring from 2-3 and now I have quick, firm shifts. No more slipping, period. This thing kicksdown quick when given some throttle and shifts great through the gears.
The kit comes with detailed instructions but as for something this complex I left it to the pros. I was billed $360 for the rebuild. Something like $135 for the kit and $225 for labor. I imagine it is similar to Maxtuning's VB mod and close to the same price. Any good tranny shop should be able to install this kit.
There are a couple of seals and springs in the box that are internal to the tranny but I haven't had an issue yet without them (knock on wood). It also comes with a cork type pan gasket but its kind of folded around the inside of the box and I already had an OEM gasket so I didnt use it.
I would definitely recommend a VB mod for all automatics and especially those that may have slipping. I cant guarantee that it will fix it but you will want it anyways for when your tranny does get fixed.
Link to write up for pulling VB.
http://www.vqpower.com/v2/articles.php?article_id=60 I think the red bolt with the ground on the bottom of the picture for step 6 does not need to be removed to pull the VB. I cant remember for sure.
VB all cleaned and rebuilt:
Whats left in the box:
And of course the HP adding sticker:
