So this article is going to help you identify the right explorer linkage for your Ninja 300 for the driving environment it is going to go through.
First things first, why you have come to read this article or even visit this website. Was it because you were facing the problem of low ground clearance with the Ninja 300 when driving solo or you were facing it when driving with your pillion. Answering this question answers half of your doubt of which linkage to go with. If one has a pillion to take care of for most of the times, the 162mm and the 170mm linkages are to go for. To answer the remaining half of the question, below detailed riding conditions are to be considered.
> Only Solo riding - Go for either the 152 or 162mm linkage.
Having a height less than 170cms - Go for the 152mm linkage to avoid tip toeing.
Having height =>170cms and wanting to have maximum comfort (least deviation from the stock bike characteristics) - Go for the 152mm linkage.
Having height =>170cms but ready to let go a bit of comfort for more gains in ground clearance for those occasional rough road trips/encounters where you are worried about a flying debris hitting your oilpan or exhaust - Go for the 162mm linkage
> Mostly Solo riding but an occasional pillion - Go for the 162mm linkage (=>170cms of height)
It would be better not to compromise your higher percentage of solo riding comfort for getting maximum possible ground clearance.
> Riding with a lighter Pillion with most of onroad distance/trips - Go for the 162mm linkage
It would be better not to compromise comfort during the long hours on the saddle rather than getting maximum possible ground clearance.
> Riding with a heavy pillion or a lighter pillion with a lot of, off the tarmac/very bad road riding conditions - Go for the 170mm linkage (=> 173cms of height)
Maximum protection for the bike underside with some amount of compromise on comfort while riding solo (a bit aggressive riding posture and stiffer ride quality for lighter riders) and with pillion (stiffer ride quality)
In general, the higher the ground clearance, better the bike underbody protection for varied road conditions, better handling due to decreased rake angle which effectively reduces the wheelbase ever so slightly and makes the bike more agile and brake a bit better due to more weight transfer on the front tyres, with a corresponding increment in compromise on comfort caused by the lifting of the rear of the bike and stiffening of the suspension. What one needs to understand here is that the small amount of discomfort which comes with the lifting of the rear, fades away in a week or two as the rider piles up more kilometers with that suspension setup and gets used to it.
So all in all, the 162mm linkage is the one which strikes the best balance between comfort and good ground clearance gains, on the other hand the 152mm and 170mm linkages are to be preferred for special needs wherein the 152mm linkage caters to shorter riders while the 170mm linkage is to be preferred in case of a heavy pillion and challenging rough terrain outings.
Hope this article will clear most of your doubts related to selection of the right linkage for your real world usage patterns.