I gave the PowerPrep Diagnostic Test 1 last night and got a 333 (169Q and 164V). I made a silly mistake in the quant section and I feel like I could’ve scored better in the Verbal section if I had a stronger vocabulary, so I’m currently working on that whilst also following the GregMat 2 month program (I’m on Week 2 Day 1 right now). I was just wondering what other material/prep could I incorporate in my quant study to get a 170. I hear Greg talk a lot about GMAT material. Which GMAT book should I refer to? Also, is there anything other than the GMAT material I should incorporate to get a 170? Thank you. 
I think as you scored so high in both section you should probably skim through 2 month and mainly focus on practicing and honing strategies.
GMAT got 2 books for Quant : GMAT OG and GMAT Quantitative Review (QR)
and each year some new questions are added to the material but as you’re mainly focusing on GRE you can even buy a 2019 or 2020 edition. Start with GMAT OG and after completing that if you still think you’re lacking then you can look at QR.
Here are all the material that Greg recommends : https://new.gregmat.com/recommended-resources
Thank you so much!