If you transfer stocks into your Personal Portfolio that are not included in your allocation, those stocks will be sold, and you will owe any capital gains taxes that are generated from those sales, unless your Personal Portfolio is held in a tax-deferred account (such as an IRA).
Personal Portfolios are held in brokerage accounts in which stocks are bought and sold, and, as in other brokerage accounts, you will owe taxes on the gains realized in any taxable Personal Portfolio account. With a Personal Portfolio, you own each and every holding - and they'll show up directly in your Interactive Brokers account. You only pay taxes on your own holdings, as opposed to (if you owned shares of a mutual fund) having to pay taxes when that mutual fund's capital gains are distributed among all of its investors.
If you are further concerned about the tax implications that are specific to your personal situation, we recommend consulting with a tax advisor.