AFAIK, Smarty Sr is the only module that will allow adjusting timing only. I think everything else is going to add either duration and\or pressure.
Timing is a mixed bag when there is not control over when and where it is applied. Too much under the right circumstances and the rings can break.
ANYTHING you add to the stock tune is going to in some way effect longevity, if thats your primary concern then leave it alone.
Dollar for dollar, pressure used correctly is going to give the biggest gain for power and efficiency. A mild pressure ramp with extra filtration is about the most effectuve way to enhance both power and efficiency and longevity.
Case in point, a friend that drives hotshot has been running a Dr P predator for the majority of the 400k he has on his truck. Excellent results on mileage and a little extra power without penalty. At 400k he is starting to have problems with injector coils and he thinks the injectors are getting a little worn. He filters ALL fuel to 2 micron.
Don't get hung up on pressure being the culprit, its quite useful and controlled correctly is still a valid way to boost power and economy. Filtration is the key on ANY setup even stock, then, make sure you know what the pressure is doing and what your EGT's are doing in response to timing and duration.
By far, the biggets percentage of failures are not cracked injectors but worn internals from etching. THAT happens on stock systems. The CR injectors are rated for way more pressure than they normally see unless one goes wild with pressure boxes, but, again thats knowing and watching what the parameters are when driving.