So here we go, I have a MY98 UK Turbo with the following mods.....

Magnex Backbox
Haywood & Scott Full Decat
K&N 57i Induction Kit
Forge V4 Dump Valve
Prodrive Intercooler Pipework
Samco Turbo Hoses kit
Dawes Device Boost Controller Running 1.1bar

Have no idea what my current BHP is, Will be tested in september at Well Lane.

Have seen many posts on Injectors & Fuel Pumps, would my car benifit from upgrading these..? if so how..?

Would there be an increase in BHP or just help the engine to run better

With my current mods my car runs very well, with no problems.

If this is a worthy upgrade whats the cost and what bits do i go for.?

Pointless unless you are going to change the turbo IMHO.