Whoa.. 90s are 58?

I just read someplace that '90 XJ's run a 58mm throttle body. So I was thinking, people notice a bit of throttle response and better airflow when switching from their 60mm to bored 62mm throttle body. So can I run a 62mm body, and a throttle body spacer and benefit from it any?

I'm already running a Magnaflow exhaust system and hollowed out cat. I'm pretty sure that theres not much resistance there and getting more air into the engine would certainly benefit right?

The 87-90 Renix motors used a TB that can be bored out to 58mm. While the HO's have one that can be bored out to 60mm or over bored to 62mm. The Renix one might be bored out to 58.5 to 59.5. Artsound on E-Bay goes that big one them. He tried 60-62, but had problems. Also, some of the castings have voids in them. I think he'd scrap 1 in 4. You can make an adapter and modify the wiring to fit an HO's TB on.
http://www.rockmodified.com/2003/april/TB/tb_perf.htm
Tom