I don't know much about turbo's yet, however I own a 90 Accord with an F series engine and a 95 Accord with a JDM H22A engine in it.
First, I assume your 90 Accord's engine is internally stock in that the internals have not been beefed up at all such as valve springs, pistons, etc. Additionally I assume you have over 100K miles on your engine. This means that the piston rings are more than likely worn from wear. From what I've heard if you install a turbo on your older f series stock engine the stress from the turbo will reduce the life of the engine quickly. Plus it's going to cost you time and money to get the turbo working on the f series engine.
So, I would agree with everyone on here. Sell your T25 turbo and save up for the H22A engine. You'll get an instant 200HP from the swap. Believe me I know first hand on my 95 Accord H22A.
Also, I'd believe Pissedoffsol about the T25 being too small for the F or the H series engine. I know nothing about turbos and he knows mucho about them.
Last, once you do the H22A swap then think about turboing it but remember if you really want to do it right you'll want to build up your H22A internals before you add a turbo so you can safely run some good turbo power and you'll be less likely to blow up your h22A.
Anyway, that's my 2 cents. I'm only passing on what I've heard from people I trust when it comes to engines and turbos.
Bruce