you're not mentioning the shipping company, how much it will cost to ship a car there, ect. i have heard too many horror stories about shipping companies damaged cars when being shipped over and i have even seen one case happen first hand

honestly its a great price if you live in florida or any near by state but if you live half way across the country like me, it isnt worth the price to ship the car, or drive it out there to have the kit installed unless that kit specifically fit your needs

OP since you live in california, just go with the stillen kit and their 9psi pulley if you need more power, dont worry about numbers ya it isnt 500whp, but 400whp is already a lot(their kit will do 420whp iirc), and its carb approved so you dont have to worry about your car potentially getting crushed for illegal mods since there is a carb sticker(ya modifying a carb kit brings it out of certification, but its also illegal for a smog shop to tear apart your car to verify everything is in spec without your permission), you wont need to worry about getting reffed for your mods

if there was another kit, even carb approved or not, id recommend it but since your choice is between GTM and Stillen, id go with Stillen