Of course the tuner will want you to buy one it's good business, seen builds for many years running stock fpr 250 plus plus I run over 200 with no aftermarket fpr. It's all about the map
I've never had a car with full interior for over 6 years I'm 30 next year..they all come back one way or another if your going to change at least buy a TT Supra ha
Don't forget to upgrade the valve springs by the time you buy decent cams get them fitted amonst other mods you could drop a fte in it seen engine going £500