Hmmm, what gearbox do you have?
Alot of people use POM or polymer material piston head as it is less stressful to the gearbox due to reduced weight.
But if you are playing semi only, then its really up to you. I have no experience with aluminum piston heads, but a consistent brand is Lonex. I'm sure SHS should be alright (if they have aluminum piston heads), but the QA is likely up in the air.
If polymer, I suggest Modify or Lonex. VS and SHS are good, but QA is slightly lower.
Btw, Sorbo is used for two things:
1) act as cushion to the force of piston head slapping on the cylinder head while reducing the noise produced
2) can aid it getting the right AOE for your piston/sector gear (instead of washers, etc.)
AOE is to adjust the angle at which the first sector tooth picks up the big tooth on the piston. This will reduce the stress on the big tooth and subsequent teeth on the piston head. If you don't adjust the AOE, you will get faster wear on the piston teeth.