Do a Single twins are too much work lol ..

4088R maybe a 37R or something .

Glenn could definately do it as he has Experience . I'd say I would do :

GReddy or Similar Intake Manifold
AEM
780cc Injectors w/Top feed rail
4088R or a PT76 GTQ
Precesion 750 IC

All the other BS Should be good for more than the stock motor could expect to handle .

A RB26 starts to get cheaper when you factor in the intake manifold and other shit you can find them for 3k if you look McKinney use to sell the RB26 w/RB25 tranny and RB20 oil pan for like 4200 . They no longer sell motors they dont install anymore though ...