Do you need a lawyer or do you not need a lawyer? Is a real estate agent all that you need to represent you? These and similar questions can be debated forever. However, in my opinion, the answers always depend on the circumstances. (Yes, "it depends" as lawyers are wont to say). Those very experienced real estate investors on the forums will likely know more about real estate transactions than many, if not most, attorneys who do not specialize in real estate. Those persons may not need an attorney. But some of the very experienced have recommended you get an attorney to assist you.
Those who are inexperienced, as you acknowlege you are, are walking into a mine field without a guide if they go by themselves. But who should "represent" you? This is a very controversialy topic and i am not going to go down that path at this time. Suffice it to say that if the person "representing" you has an interest in whether you make this particular purchase or not because his/her commission depends on the sale, that person has a conflict of interest and cannot "represent" you without reservation. Of course, some attorneys are not trustworthy, so reputation is very important in selecting someone to "represent" you.
And if you do hire an attorney experienced with real estate transactions, at what point should you do so? Although a real estate purchase is often the largest purchase a person will ever make, all too many buyers (and sellers for that matter) seem to hire an attorney only AFTER they have signed the contract. Once the contract is signed, there is a binding agreement and while there are ways to get out of a contract, nonetheless it may be difficult if the wrong contract is used without adequate protections for the buyer. Further, once a contract is signed, any promises made by a seller or agent that are not included in the contract in writing, are typically unenforceable.
Finally, the PAR contract is a good one and can be purchased from PAR, or a sample can be downloaded from the web (with the word SAMPLE written across it). However, even that contract contains provisions and options that require guidance for the inexperienced purchaser.