Investing in coins have nothing to do with forum rank.
You need merit and activity, both of them to increase your rank.
Wish the OP luck on ranking up for it seem so hard now especially if one is not that good poster. If you had good English well then you got a better chance on receiving merit and rank up. Local boards is not also a guarantee for one to get merit because some of the local boards do not have a source merit.
There are other factors also that will enable you to rank up and that is by being good technicay with computer and share it here in the forum.
And if you will be able to find it hard to get merit then do not blame the admin of this forum. The merit system was introduced to reduce spam and pointless post. So blame the spammer not the admin of the forum. Spammer kills the newbie to rank up.