Pushing pretty much always increases contrast (assuming normal devs). Personally, if you want more grain, I might suggest shooting Tri-X. If you want more contrast (depending on how much more you want), are you sure that pushing is the way to go about it? I'm not saying it isn't, but assuming you are scanning, just give your file a tweak in curves for more contrast. It's the equivalent of printing on a higher grade of paper. Most people's flat scans are FAR lower in contrast than grade 2 paper would give you...
If you do want to push, I've never found that pushing actually increases the grain as much as moving up to the next faster film in the family (i.e. Tri-X) or switching to a grainier make. Diafine will give you (sorta kinda) more speed, maybe 320 or 400, but it does funny things with contrast compared to normal devs since it's compensating. It's a great choice, but might not be the right thing for 'more contrast'.
Good luck with examples. People's techniques are all over the place so it can be really hard to judge this stuff without doing it yourself.
