tdo6 20g
http://www.boostplanet.com/product6.htm
Avo450 would be an option. Ball Bearing 450bhp turbo.
td06 20g is a 49lb compressor wheel
18G comp wheel = 38 lb/min flow
SZ49 or FPGreen comp wheel = ~49 lb/min flow or around 490 bhp
SZ55 comp wheel = ~55 lb/min flow or around 550 bhp
SR40 = ~42 lb/min comp wheel flow or around 400 bhp
SR50 = ~50 lb/min comp wheel flow or around 500 bhp
SR55 = ~57 lb/min comp wheel flow or around 550 bhp
AVO400 = 40 lb/min comp wheel flow or around 400 bhp
AVO450 = 44 lb/min comp wheel (biggest AR bolt on turbine housing I know of)
AVO500 = ~50 lb/min comp wheel (same turbine housing as AVO450)
SBR20G = same comp wheel as any other 20G
SBRGT10 = 44 lb/min comp wheel flow
SBRGT11 = 50 lb/min comp wheel flow
SBRGT12 = 55 lb/min comp wheel flow
sr40 would be similar or close to a Pe1820, but i could be wrong. But i hear good things about the avo450 and the td06 20g. Avo450 is a 44lbs wheel so somewhere in between a Pe1820f and a td06 20g. Less lag good power, but costly.