'98 S70 T5 manual
 

I have had this car for almost 10 years (134,000mi) and made various performance mods (turbo back exhaust, upgrade fuel injectors, IPD air intake, RIP and ECU flash etc). It has always seemed to be stronger than what the numbers were supposed to be. It recently came to my attention that there is a Volvo S70 1998 2.3TR Power: 247 hp in addition to the Volvo S70 1998 2.3T5 Power: 237 hp that I thought I had.
Today, I found this on Volvo VIN Decoder Tool Online
This VIN is from a 1998 Volvo S70 T5 2.3 250hp Engine Code: B5234T3
Is there a way to determine what hp I started with and if there are different T5 engines?

there's a whole Wiki on the Volvo modular engine series which shows each iteration by engine code.

https://en.wikipedia.org/wiki/Volvo_Modular_engine