There are actually 2 different T88 kits that Greddy offers in Japan, 1 of them is a 33D and the other one is the 34D kit. The 33D kit comes with the Type C wastegate, and the 34D kit comes with the Type C "Hi Flow" version wastegate. The 34D kits are the ones we get here in the USA, so for all intents and purposes the 34D kit is the one we're discussing here, it comes with a 21psi spring for the wastegate with the kit. Here's some stuff that I got from the Trust website in Japan about the kit:

T88 33D or 34D
(User selection)
* SUS45 φ EX マニ
* W/G type C or type C
High flow selection
* 94 φ couplings
Front tube
* AIRINX AY-M

Remark 1) GReddy I/C KIT exclusive use, TR muffler exclusive use & note: 94 catalyst adapters (another sale) by use, also installing other than the genuine catalyst, and the TR muffler is possible